Meat eating made us human. The anthropological evidence strongly supports the idea that the addition of increasingly larger amounts of meat in the diet of our predecessors was essential in the evolution of the large human brain.  Our large brains came at the metabolic expense of our guts, which shrank as our brains grew.

In April 1995 an article appeared in the journal Current Anthropology that was an intellectual tour de force and, in my view, an example of a perfect theoretical paper.  “The  Expensive-Tissue Hypothesis” (ETH) by Leslie Aiello and Peter Wheeler demonstrated by a brilliant thought experiment that our species didn’t evolve to eat meat but evolved because it ate meat.

The ETH is an example of the kind of scientific detective work I love.  In fact, this paper is one of my all time favorites.  (An amazing bit of trivia about this paper is that it almost didn’t get published.  I had the opportunity to talk with Leslie Aiello at a meeting a few months ago, and she told me the journal was reluctant to publish the paper because the editors thought it too technical for their readers.  I suspect they also found it too controversial.  Now I’m sure they’re glad they published because I would imagine it is the most cited of all the papers ever published in Current Anthropology.)  The authors methodically lay the scientific foundation for their experiment, then, like Sherlock Holmes, progress step by step, accumulating little pieces of data until they reach the ineluctable conclusion that meat eating made us human. I would like to walk us all through their thought processes as laid out in their brilliant paper.

Let’s start with the problem.

For years anthropologists have speculated about why humans developed such large brains so quickly – from softball size to what we have now in just a short 2 million years.  Below is a graphic showing hominid/human brain growth over time.

ETH brain growth

A number of hypotheses have arisen to answer this question.  Some say that humans developed large brains because they had to contend with problems involving group size, others posit that large brains came about as a consequence of developing complex foraging strategies, others yet say the development of a social or Machiavellian  intelligence was the driving factor.  And even others say that the complexities of learning to hunt expanded brain size.

Any or all of these hypotheses may be valid, but the problem isn’t really as much a matter of why as it is a matter of how.  Other primates deal with groups and have complex foraging strategies; and many deal with social problems within their groups, and some even hunt.  Yet they still have small brains.  (Granted, their brains are larger for their size than those of other mammals, but primates sport small brains as compared to humans.)  How did the human brain grow?

This isn’t an easy question to answer because of the thermogenics involved.  Brains consume a large amount of fuel and, consequently, throw off an enormous amount of heat for their size.  The metabolic rate of brain tissue is nine times that of the average of  the metabolic rate of the rest of the body.

So what? you may say.  So we’ve got a big, hot-running, energy-burning brain.  What difference does that make?  It’s reflected in our overall metabolic rate, right?  Well, sort of, and therein lies the crux of the problem.  As we will see below, our total metabolic rate – even with our huge brains – is the same as that of any other animal our size. Or to say it another way, animals our size with much smaller brains have the same metabolic rate that we do with our huge brains.  This fact was the starting point for the authors of the ETH.  So let’s start there as well.

In keeping with a great scientific tradition, Aiello and Wheeler were able to see what they saw because they stood on the shoulders of giants who came before them.  In their case the giant was Max Kleiber, an animal physiologist working at the University of California at Davis, who published a groundbreaking paper in 1947 and a scholarly text titled The Fire of Life in 1961.  Kleiber’s work involved the meticulous measurement of the metabolic rates of numerous animals, including humans.  As he plotted the various metabolic rates, he discovered an extremely strong correlation between the mass of an animal and its metabolic rate.  Kleiber found that this relationship held constant across numerous species.  His October 1947 paper in Physiological Reviews simply titled “Body Size and Metabolic Rate” was a classic.  By using the equations Kleiber worked out, the metabolic rate of virtually any animal could be determined simply by knowing the animal’s body size.  Or, as Kleiber put it in the paper:

Does a horse produce more heat per day than a rat or do some rats produce more heat than do some horses?  Almost anybody who understands what is meant by “heat production per day” will not hesitate to give the correct answer and will even be convinced that the daily rate of heat production of men or sheep is greater than that of rats, but smaller than that of horses.  Thus most people (among those who understand the question) are convinced that in general the bigger  homeotherms produce more heat per day than the smaller homeotherms, that, in other words, the metabolic rate of homeotherms is positively correlated to body size.

The answer to the next question: “does a horse produce more heat per day per kilogram of body weight than a rat?” requires some biological training.  Most biologists, however, will not hesitate to answer that the rate of heat production per unit body weight of the big animal is less than that of the small animal.

The positive correlation between metabolic rate and body size, and the negative correlation between metabolic rate per unit weight and body size, establish two limits between which we expect to find the rate of heat production [basal metabolic rate] of a horse if we know the rate of heat production of a rat.  We expect the metabolic rate of the horse to be somewhere between that of the rat, and that of the rat times the the ratio of horse weight to rat weight, provided of course that we do not regard these two correlations as simply accidental.

If we are firmly convinced that the metabolic rate of horses, and other homeotherms of similar size, is never outside these two limits, then we admit to recognize a natural law between body size and metabolic rate.

This natural law, carefully calculated by Kleiber, is now known as Kleiber’s law.  Below is Kleiber’s law graphed out by him as it appeared in his seminal paper.  And this is exactly as it appeared in the journal, but with the addition here of colors for better legibility.  Since their was no Excel nor graphics software in Kleiber’s time, the graph was hand drawn and appeared in the pages of Physiological Reviews as such.  How times have changed.

Kleiber line blog

As you look along the line running from lower left to upper right, you can find rats and horses and a host of other mammals including humans.  Over the years, mammals that Kleiber didn’t have the opportunity to work on have been measured, and they all fit nicely along Kleiber’s line, following Kleiber’s law.  Because of this tight correlation, Kleiber’s equations can be used to precisely estimate the metabolic rate of any animal just by knowing its size.

Aiello and Wheeler used Kleiber’s law as the jumping off point for their grand thought experiment.

Since all animals measured have conformed to Kleiber’s law, Aiello and Wheeler postulated that animals now extinct – including our human and pre-human predecessors – would have fallen along the same line. Using skeletal remains paleontologists have been able to calculate body sizes of extinct animals along with pre-Homo and early-Homo species.  Then using Kleiber’s law, it is possible to closely estimate the metabolic rates of these creatures.  And here’s where it gets interesting.

According to Kleiber’s law, an australopithecine weighing 80 pounds would have the same metabolic rate as a human weighing 80 pounds despite the disparity in brain size between the two.  The much larger brain of the human would have 4-5 times the metabolic rate of the brain of the australopithecine, yet would have the same overall metabolic rate.  What gives?

That’s precisely what the authors of “The Expensive-Tissue Hypothesis” wondered.

Because the human brain costs so much more in energetic terms than the equivalent average mammalian brain, one might expect the human BMR [basal metabolic rate] to be correspondingly elevated.  However, there is no significant correlation between relative basal metabolic rate and relative brain size in humans and other encephalized animals.

Where does the energy come from to fuel the encephalized brain?

The authors postulated a solution.

One possible answer to the cost question is that the increased energetic demands of a larger brain are compensated for by a reduction in the mass-specific metabolic rates of other tissues.

In other words, if one organ – the brain, for example – is chewing up a lot of energy and contributing a disproportionate amount of the basal metabolic rate for the animal as a whole, then maybe another organ or group of organs are consuming less energy to compensate.  The heart, the kidneys, the liver, the skeletal muscles, the GI tract – all consume energy and contribute to metabolic rate.  Maybe one of these organs became smaller as the brain became larger over time.

We can hone our analysis a little finer if we begin to look at an energy-balance equation, but an energy-balance equation of a different kind.  I have written a number of times in this blog about the energy-balance equation that applies to weight loss: change in weight equals energy in minus energy out.  That is not the equation we’ll be talking about here.  The other energy-balance equation says that the total metabolic rate is the sum of all the metabolic rates of the various organs and tissues in the body.  If you add the metabolic rates of the kidneys, the heart, the brain, the muscles, the digestive tract and so on together, you will get the total metabolic rate of the body, which makes sense because it is the sum of the parts.

Total BMR = brain BMR + heart BMR + kidney BMR + GI tract BMR + liver BMR + the remainder of the body’s tissues.

The authors of the ETH set out to look at the metabolic rates of the various organs.  By a diligent search of the literature, they found that along with the brain, the the heart, the kidneys, the liver and the gastro-intestinal tract account for the vast majority of the total BMR.  They dubbed these organs as ‘expensive tissues’ because they consume a large amount of energy as compared to their size.  (Surprisingly, muscle mass doesn’t contribute all that much to the total metabolic rate (skin and bone contribute even less), which gives the lie to that old notion — that I, myself, have fallen prey to — that replacing fat with muscle increases metabolism significantly.)

Aiello and Wheeler reasoned that if the total metabolic rate stayed the same while the energy-expensive brain grew over time some other expensive tissue had to get smaller.  There could be no other solution.

But which of the expensive tissues got smaller?

Aiello and Wheeler examined the data on the metabolic rates and sizes of the various expensive tissues and learned that for a 65 kg primate, the heart, the kidneys, and the liver were approximately the same size as those of a 65 kg (143 lb) human.  The greater metabolic rate of the large human brain was compensated for by a GI tract significantly decreased in size.  It turns out that the GI tract of a 65 kg human is just a little over half the size of the GI tract of a similar sized primate.

The combined mass of the metabolically expensive tissues for the reference adult human is remarkably close to that expected for the average 65-kg primate, but the contributions of individual organs to this total are very different from the expected ones.  Although the human heart and kidneys are both close to the size expected for a 65-kg primate, the mass of the splanchnic organs (the abdominal organs) is approximately 900 g less that expected.  Almost all of this shortfall is due to a reduction in the gastro-intestinal tract, the total mass of which is only 60% of that expected for a similar-sized primate.  Therefore, the increase in mass of the human brain appears to be balanced by a almost identical reduction in size of the gastro-intestinal tract.

Below is a graphic from the ETH showing the sizes of the different organs as based on predictions from a 65-kg primate and the observed size in humans.

ETH body comp compare

So we know that as humans evolved larger brains they simultaneously co-evolved smaller guts in order to maintain a set BMR.  And this is where the story gets interesting. Why?  Because

the logical conclusion is that no matter what is selecting for brain-size increase, one would expect a corresponding selection for reduction in the relative size of the gut.

Some researchers believe that increasingly complex activities drove the brain to enlarge.  As the authors of the ETH summarized it:

The relationship between relative brain size and diet is often mentioned in the literature on primate encephalization and is generally explained in terms of the different degrees of intelligence needed to exploit various food resources.  For example, [some] have argued that a relatively large brain and neocortical size correlates with omnivorous feeding in primates , which requires relatively complicated strategies for extracting high-quality foodstuffs.  Alternatively, [others] have suggested that frugivores have relatively large brain sizes because they have relatively larger home ranges than folivores, necessitating a more sophisticated mental map for location and exploitation of the food resources.

But it doesn’t matter whether our brains got big because our predecessors were socialized, developed complex foraging strategies, lived in and had to deal with groups or were skilled hunters, in order to obey Kleiber’s law, something had to force our guts to get smaller at the same time.  What could that be?

According to Aiello and Wheeler, it was increased diet quality that allowed the gut to get smaller while still absorbing the necessary nutrients to fuel the metabolism.  As they put it

The results presented here [in the ETH] suggest that the relationship between relative brain size and diet is primarily a relationship between relative brain size and relative gut size, the latter being determined by dietary quality.  This would imply that a high-quality diet is necessary for this encephalization, no matter what may be selecting for that encephalization.  A high-quality diet relaxes the metabolic constraints on encephalization by permitting a relatively smaller gut, thereby reducing the considerable metabolic cost of this tissue.

What the authors are saying is that it doesn’t matter how much more brain power was required, the brain couldn’t enlarge without something else giving.  What obviously gave was the size of the GI tract, and the only way a smaller GI tract could provide the fuel for the body was to have a higher-quality diet. How did the our most ancient relatives the early hominids increase the quality of their diets?

A considerable problem for the early hominids would have been to provide themselves, as large-bodied species, with sufficient quantities of high-quality food to permit the necessary reduction of the gut.  The obvious solution would have been to include increasingly large amounts of animal-derived food in the diet.

Increasing the amount of easily-digested food of animal origin allowed us to shrink our guts while expanding our brains.  Had we remained on a diet high in vegetation, we would no doubt not have been able to expand our brains irrespective of how much more thinking those brains would have needed to do.  It just wouldn’t have been possible to do so without violating Kleiber’s law.

Take the gorilla, for example, almost pure vegetarians that spend their entire ‘working’ day foraging and eating, which they have to do to get enough calories to maintain their enormous bulk.  They have large guts and pay for it by having small brains.  Even smaller than that of our most primitive ancestors, the australophthecines.

Gorilla has one of the lowest levels of encephalization of any haplorhine primate, and the much higher level of encephalization of all the australopithecines suggests a diet of significantly higher quality than that of this genus.

Which makes sense when you consider that carbon 13 isotope analysis has shown that Australopithecus africanus (the species that came right after Lucy) consumed meat.  As you go up the lineage from Australopithecus and through Homo, you find that more and more meat was consumed the higher up the tree you go.

It’s easy to see that, as compared to humans, chimps and gorillas have large, protuberant bellies, which supports the fact that they have larger GI tracts, but what about our ancient ancestors.  All we have to go on are skeletal remains, which show nicely that their heads (and brains) were much smaller than ours, but what about their guts?  How do we really know their guts were larger?  According to Kleiber, they would have to be, but how to we really know they were?

The large gut of the living pongids gives their bodies a somewhat pot-bellied appearance, lacking a discernible waist.  This is because the rounded profile of the abdomen is continuous with that of the lower portion of the rib cage, which is shaped like an inverted funnel, and also because the lumbar region is relatively short (three to four lumber vertebrae).

The drawing below from the ETH shows the inverted-funnel shape of the ribcage of the chimpanzee on the left.  You can mentally draw the lines downward from these ribs and envision the pot-bellied look of the abdomen that these primates evidence.  Looking at the image on the right, you can see that Australopithecus afarensis (Lucy’s species) has the same inverted-funnel shaped rib cage, indicating a large belly and a low-quality diet.

The drawing in the middle is of a modern human.  If you extrapolate the lines down from the human rib cage, you can see that they lead to a more narrow waist.  Makes you think more of a lean, rangy wolf or other slim-waisted carnivore, whereas the other two don’t.

ETH rib cage

The authors conclude:

If an encephalized animal does not have a correspondingly elevated BMR [which according to Kleiber, it can’t], its energy budget must be balanced in some other way.  The expensive-tissue hypothesis suggested here is that this balance can be achieved by a reduction in size of one of the other metabolically expensive organs in the body (liver, kidney, heart of gut).  We argue that this can best be done by the adoption of a high-quality diet, which permits a relatively small gut and liberates a significant component of BMR for the encephalized brain.  No matter what was selecting for encephalization, a relatively large brain could not be achieved without a correspondingly [sic] increase in dietary quality unless the metabolic rate was correspondingly increased.

At a more general level, this exercise has demonstrated other important points.  First, diet can be inferred from aspects of anatomy other than teeth and jaws.  For example, an indication of the relative size of the gastro-intestinal tract and consequently the digestibility of the food stuffs being consumed is provided by the morphology of the rib cage and pelvis.  Second, any dietary inference for the hominids must be consistent with all lines of evidence.  Third, the evolution of any organ of the body cannot be profitably studied in isolation.  Other approaches to understand the costs of encephalization have generally failed because they have tended to look at the brain in isolation from other tissues.  The expensive-tissue hypothesis profitably emphasizes the essential interrelationship between the brain, BMR, and other metabolically expensive body organs.

I hope you are now armed with enough knowledge to be able to see through these articles and/or charts that are all too common showing how the GI tract of humans is closer to that of a gorilla than it is to that of a cat or some other carnivore.  It seems to me that Aiello and Wheeler have pretty thoroughly demolished the notion that humans are actually designed by the forces of natural selection to be vegetarians.  Based on the data and the argument they present, it is actually the opposite:  we evolved to be meat eaters.

It was our gradual drift toward the much higher quality diet provided by food from animal sources that allowed us to develop the large brains we have.  It was hunting and meat eating that reduced our GI tracts and freed up our brains to grow.  As I wrote at the start of this post, the evidence indicates that we didn’t evolve to eat meat – we evolved because we ate meat.

Lierre Keith had it right in The Vegetarian Myth:

The wild herds of aurochs and horses invented us out of their bodies, their nutrient-dense tissues gestating the human brain.

If we evolved because we ate meat, why would we want to stop now?

Note: I found the full text of this article available on Scribd.  If it gets taken down, let me know, and I’ll put it up here.  I’m just trying to save space on my server.

Painting at top: Monkey Before Skeleton by Gabriel Cornelius von Max


  1. Good stuff. I’m curious to see how Tim’s avid vegan/vegetarian readers respond though (if any take the time to read it).

    1. Probably proof that no matter how much meat you eat and how big your brain gets, you can still be ignorant.
      Tying meat-eating to brain size does not explain our evolution. It is diversity and adaptability that allows a species to thrive. We are omnivorous, which means humans can survive in many different places under different conditions.
      Eating factory-farmed meat three times a day is harmful to the environment, locally and globally, wastes energy, and contributes to more water waste than anything else, since you have to more irrigate crops to feed them to animals instead of directly to humans. Besides, when we started eating meat we weren’t using chemicals, hormones, and cruelty to do it.

      1. Totally agree Anna!.

        It’s dangerous to base our diet in paleo/primal theories. Craving for energy dense food (meat) and eating as much as you can is a good thing when you live in resource scarcity and you are forced to physical activity. But now, with food super abundance and lack of excercise, it leads to obesity and related diseases.

        Perhaps it’s not a bad idea to base our diets in “low quality” food provided we can get all the calories we need to maintain our big brain

        1. Anna, you are wrong. If you eat low-quality food you will be hungry, and you will likely eat more calories than you would on a high-quality low carb diet. People on low-carb diets tend to restrict calories even if told to eat all they like.
          Growing grains and soy to feed humans or livestock destroys the environment. Raising livestock on pasture preserves much of the natural balance; raising game is even better. Because fish makes good fertilizer, vegetable growing even contributes to overfishing.
          When I was mainly vegetarian I was always hungry and went through much more food than I do today. It’s false economy (and false environmentalism) to think that “low quality” food staples like grains and legumes have to be superior to animal foods.

          1. On what scientific basis would grains, beans, and legumes be considered low quality. Calorie for calorie, they provide more protein, fiber, and vitamins than meat?

            And how could you have been hungry being a vegetarian? Meat has no fiber, you can be hungry an hour after eating a chicken breast. Try that on a cup of beans with 16 grams of fiber (along with 16-18 grams of lean protein) – your good for hours.

            Raising livestock is the #1 source of pollution today. Cars and other pollutants are #2. Sure having a few cows graze on a pasture on alternate seasons is good for the land. Having 10 billion animals raised every year for food is a disaster. Nitrogen is depleted from the land, which makes it useless (plants put it back), pollution from the animal waste infects water and land, and of course, how can you ignore how polluted the meat we eat is. The fish argument is ridiculous, even more so when you consider that over 90% of what is grown in the US is grown to feed the animals, along with most of our water and power.

            You also can’t raise animals in factory farm conditions and not be forced to treat them with mass antibiotics. Also, last time I checked, dairy cows, like humans, do not lactate year round. How natural do you think that milk you drink is?? The hormones they’re pumped full of to produce that disgusting milk (what animal drinks milk beyond infancy and from another species????) is absolutely, tied to cancer (even to some twin births), not by vegans, but by the government. People so against vegetarians often fail to realize that the facts we produce, are straight from official sources and not just an opinion or something we just made up.

          2. Fibre is not the be all end all you make it out to be. Fibre can actually be harmful to the digestive tract.

            Yes, you can be hungry an hour after eating a chicken breast. This is because it is lean. And you can be hungry an hour later eating a cup of beans as well. What stops you from getting hungry for hours is the amount of fat you consume.

            Raising animals in factory farm conditions is a US trait. Same goes with treating them with mass antibiotics. In Europe we have rules that stop this sort of process. All the animals are raised in pasture.

            And raising animals on pasture replaces the nitrogen into the land when animals urinate. Plants do not put nitrogen back into the land. This is trypical vegan/vegetarian propaganda. Plants LEACH minerals etc from the land. Animals are responsible for putting some of these goodness back into the land. Same goes with water, as most water is consumed by agriculture – meaning plant farming.

            Vegans/vegetarians should really get a clue. You spout the same tired crap that is shot down again and again and again. Don’t you realise that you are talking to a brick wall because NOBODY but FOOLS believe you any more?

          3. Why your right I couldn’t have been hungry on such high-quality fibre.
            No doubt the whole experience was just a hallucination due to B12 deficiency and vegan psychosis.

            I thought it was vegetarians who depend most on dairy for good nutrition, meat eaters don’t need it.

            Why would I eat a chicken breast? That’s lean meat that only appeals to vegetarians.

            Eat the fat, then you don’t waste half the animal. If everyone started eating fat again instead of those extra grains and sugars we could feed a lot more people with the same amount of livestock.

          4. “Raising livestock on pasture preserves much of the natural balance”
            Totally does. I’m a vegetarian (just for the nfo)
            I’m not against the idea of livestock grazing grass on the pastures and ppl, who looked after them and who took care of them all their lives, to eat them later on. yes, it’ still wrong if your asking my vegetarian ethics code, but still it’s better than what’s really happening: this isn’t real in most cases!
            Livestock isn’t happily grazing on a beautiful pasture.
            they are being fed in the farm. See Earthlings to get the picture.
            Forests are being destroyed so that people can make the damned pastures AND use the land to make crops to feed the pigs you eat at McDonalds.
            What part of the equation “less trees + more living creatures = more CO2 and tons of methane” improves the balance?
            however…cows grazing on pastures…nice. I wouldn’t kill the cow and eat it but I’d better have the animals living on pastures rather than in closed farm cells before they got killed and eaten.

          5. This is the real picture in the countryside where I live – pastured animals – yet we get fed exactly the same vegan BS. Their message isn’t affected by the actual conditions here being different to the ones they read about online.
            Some people don’t mind being dependent on animals, others seem to resent it, but sentimentalize that resentment.

          6. George, I agree that grains & legumes are low quality foods. Humans are physiologically not grain eaters. Just as we are not meat eaters. Yes, many vegetarians are in as bad a shape as the majority of society because they continue to eat a highly processed, cooked diet of grains & starches. Your problem was not eating enough calories from the highest quality foods on the planet…fruit. Eat bananas, figs, dates, etc daily and you will never be calorie deficient. Biologically we are frugivores, that is a fact. Do the research and you will agree.

          7. Show me this research. I have looked at the evidence and it is not convincing. Where are you hiding this research? Where do the Inuits get all this fruit? Did the Masai just herd all those cattle to keep them as pets, our did they not nourish themselves with the meat, fat, organs, blood, and milk?
            We evolved to burn fat for energy and THAT is fact. Do the research and you will agree. Fat and the derived ketones provide clean and efficient energy and keep the mitochondria running smoothly and not swamped by ROS. Fruit should be kept to small quantities and consumed when seasonally available, not shipped across the globe.

          8. Do our teeth look like the teeth of meat eaters? Isn’t it odd that all the other meat eating mammals have similar teeth (you know, to eat flesh with easier), yet ours aren’t like that. Are you saying that because we have bigger brains our teeth changed because our bodies knew we could eat meat another way (by using our big brains)?

            We also don’t eat like meat eaters at all. We have to chew our food really well before swallowing it. Meat eaters eat their food far more whole than we do.

        2. seriously. your kidding right. you get fat from eating protein based foods but not from carbohydrate food. a man a lot smarter than you or i figured out we are natural hunters and therefore meat eaters and eating that keeps us lean and fit and is good for our kids to eat also. we have always been hunter gatherers from the very first time our ancestors opened there eyes.

      2. I totally agree, especially since iI am now taking the course, Plant-Based diet based on the book- the China Study.

      3. It makes sense though & if you follow it, you’ll find you eat less ( don’t need 3 meals a day. You’re getting the nutrients from smaller amounts of food. How can the earth sustain all the vegetables the population need. The veggies are lacking magnesium & other nutrients as a result of mass production. I bought basil that had no fragrance?

    2. What if I became a vegetarian/vegan cause I saw and didn’t like it the way animals are treated at the farms and slaughter houses… Am I a an idiot as well? All this article proofs to me is that eating a cow which spent her life eating grass and being free is healthy. Animals we eat these days are packed with hormons, antibiotics, they sick, they suffer, they are unhappy, they are force to produce milk, eggs, they beaten, they hardly ever see the sun. This list is very long….. I like meat, but thank you very much… I rather be a vegetarian, an idiot as you call it! And don’t forget that any idea can be proven these days, but it isn’t about that. Most people I know became vegetarians cause they wanted to say NO to animal abuse.

      1. Just yesterday I visited the farm where the eggs, meat and milk I buy come from and all of the animals there seemed very happy and have plenty of space. They are all pasture raised and there is no use of antibiotics or hormones or any inhumane practices. Do not act like it is not possible to buy animal products from farmers who raise animals the proper way.

    3. Believe me nobody is doubting anthropology. I am sure vegetarians understand that. It’s the analysis that makes me gasp. Vegans r talking about something more profound. We are talking about ethics. Is it ethical to convert an animal into a product for no other reason than taste?

      The concept of ‘animal rights’ values the simple premise that ALL living creatures have a “right” to be allowed to live their lives without victimization–free from brutality. It is a right that EVERY being strives for.

      Would that kind of merciful thinking really make you an idiot? I seriously doubt it.

      1. You got it right, non-vegetarians think that your kind of logic makes you an idiot, only no one says so because it it rude, but since you just asked…
        In my mind eating animals provides all necessary nutrients that you can’t substitute with supplements So, I see a vegetarian way of eating as a form of a human sacrifice, or at least human health sacrifice. There are always some self-destructive individuals among human population, so if you are the type, go ahead and fulfill your mission. Your wish to be considered a smart person at the same time is too unrealistic . I wonder how many people are really upset that tobacco farmers are straggling right now and want to sacrifice their health by smoking in order to support the tobacco industry. By the way, it keeps some smokers slim. (A while ago I watched a pbs movie about Virginia farmers going out of business and felt really sorry for them.) I am giving you a credit for not representing you religion as a healthy life-stile. Among things I asked my son to avoid before he went to college “Stay away from vegetarians” went right after don’t drink too much. The thing I do that contributes to animals well-being is paying for a pastured meat. Consider prices, it is not a little . I invest in my health and more sustainable farming at the same time..While you contribute to a habitat destruction by agriculture. Just think about it.

      2. What about the many other predators that roam the earth? Many that will begin eating their prey before its dead. The predators that use poison and watch the prey slowly die, waiting for it to be weak enough to start consuming it? Does a pride of lions sit around pondering why the nearby zebras should not be killed for taste? It is nature, and we are a part of it. Plants are living organisms too, shouldn’t they be able to have a life with out being chopped up? The poor carrot being ripped out of the ground, barely being kept alive by a water spray, until you take it home, chop it to pieces, throw it in boiling water. It doesn’t matter for them though, they don’t have the bambi eyes, or the mouths to cry out.

        You want to fundamentally change nature, to you its okay for a wolf to eat deer, but bad for a human to do it. Its fine a killer whales to eat seals, bad for humans too. It is the archaic thinking that we are somehow above nature when we are a part of it, and always will be.

      3. So, by your standards, we shouldn’t kill bugs, rats and other pests even if they decimate the crops?

  2. Maybe that joke was in poor taste. I just wanted to say that this is an amazing blog post, worthy of award (if such things exist). This is just the kind of writing we all need – someone to take good research that may be over our heads, and explain it to us piece by piece. Thank you so much!

    Let’s try to get this on Digg

    I would be clueless as to how to get something on Digg. What do I have to do?

  3. I guess this means that instead of eating we can inject already broken down nutrients and get even bigger brains. Fascinating.

    This was quite convincing. Eating meat evolved our brains. But now that we have big brains and small GIs, what happens now if we substitute meat for vegetables? Will my brain get too little energy if I eat lots of vegetables and not so much meat? Will this make me less smart? Sodas might make up for (hypothetically) decreased consumption of meat?

    A little grammatical error in “As you goes”. Really great article. You have material for writing hundreds of books. Why have you written so few? 🙂

    Thanks for the heads up on the error – I’ve fixed it.

    Writing books is a pain. Plus no editor would buy a book filled with a lot of the stuff I post in this blog because he/she wouldn’t think it would sell because it would be over the head of the average reader. By and larger, editors (the ones who buy the books) don’t have a very high opinion of the reading public.

  4. Hi Dr Mike.
    Thank you for writing so well in bringing another interesting scientific narrative to our attention. I’ve downloaded the paper from ScribD so I can read it more deeply myself.
    I also like the picture; I am particularly intrigued by the pen, paper and the steady, contemplative, even intelligent gaze of the monkey. Gabriel van Max was an interesting character and seemingly love his monkeys.

    May I also say that you give a great visual impact to your posts by using the coloured illustration, whether painting or photograph. Clearly you have design and artistic skills as well as superb writing ability!

    BTW shouldn’t “brilliant though experiment” be “thought” in second para above?

    On supine SAD and VAT I found the following paper

    which includes using coronal abdominal diameter with SAD to estimate viscerality.
    I just love the stick figure representations showing where measurements were taken!

    I’m now off to have the 1st coco milk shake of my day, on 10th day of liver detox.

    Y’all take care, now.

    It does say ‘brilliant thought experiment’ now. Thanks for the heads up.

    I never thought about it vis a vis the pictures I put up on this blog, but I suppose I do have some artistic skills.

    I think you sent the wrong paper. The one above is about metabolic syndrome and erectile dysfunction.

  5. Dear Dr Eades

    Fat, Protein and Nephritis

    Many thanks for this and the previous blog on meat eating…excellent stuff.

    You name checked Stefansson on Sept 17. He, and some other polar explorers of the late 19th and early 20th century, noted how they thrived on meat only diet. Nansen, for example, when his supplies ran out, had to exist off a meat only diet based on what he could hunt and kill.

    I should like to quote Donald B Macmillan writing in 1920, recalling his time with Peary on their 1908/09 attempt on the Noth Pole:

    The men…”in quest of musk-oxen, caribou, and Arctic hare: for Peary, who never had a single case of scurvy on any of his expeditions, fully appreciated the value of fresh meat as an antiscorbutic. Fresh vegetables, acids, and fruits are not necessary. This fact we have known for at least a half century, having acquired it from the experience of the American whaling captains. Scurvy stricken patients were always dispatched by them immediately to the igloos of the Eskimos, there to be restored to health by consuming raw frozen meat.”

    However, during Stefansson’s ill-fated Karluk expedition in 1913-1914, the men, living on mainly pemmican, were stricken down with a mystery illness. It turned out to be nephritis. To quote from Jennifer Niven in the “Ice Master”:

    “The mystery illness was nephritis caused by too much protein and fat in the diet. The very pemmican that had been keeping them alive had also been killing them. As long as they had had biscuits, they were fine, but without carbohydrates in the biscuits to balance their intake of protein, they were doomed. The fresh meat had been much better for them than the pemmican, but there had not been enough of it. It was the pure pemmican diet that had killed Mamen and Malloch, and it was the pemmican that had made the rest of them so desperately ill. Before the expedition began, Stefansson had damned the purity tests and purchased the pemmican without having it analyzed”.

    The quote does stress the difference between fresh meat and pemmican, but could you perhaps provide some further details on nephritis and excess protein and fat and her comment on carbohydrates?

    She is incorrect. As far as I know, there is nothing in biscuits that will ‘balance’ protein. Too much protein alone can cause problems (Stefansson referred to the problem as rabbit fever), but if protein is consumed with either fat or carbohydrate (or both), the problem goes away. Pemmican is made of jerky and fat, and, according to Stefansson, many people have survived for long periods on jerky alone, so I doubt the deaths were caused by the pemmican unless the pemmican were somehow tainted.

  6. Terrific article. You know, Doc, I’d have to sit down and think about it for awhile in order to come up with a longer list, but from all my reading, including now this, it sure seems like we are amassing a number of “discoveries” that completely flip what we previously thought was correct cause and effect. There’s this meat/brain one, and there’s “people don’t get fat because they’re lazy, they’re lazy because they’re fat”. There’s “the taking on of challenging academic subjects doesn’t make you smart, it’s because you are already smart that you are drawn to challenging academics”. And being depressed and anxious don’t cause you to have debilitating thoughts and actions, it’s the “chosen” types of thoughts that cause you to be anxious/depressed.

    Amazing. What’s next?

    Who knows? Glad you enjoyed the post.

  7. Thanks for this wonderful summery. But, woe and double woe, the 6 Week Cure still hasn’t made it here yet! Bloody Amazon only offered one option for shipping to Australia and it’s obvious that the runner with the forked stick died on the way.
    But I can offer you something of beauty in return! Mr Postman left me the latest Brahms recording in the Sir John Eliot Gardiner series and it contains some amazing choral gems some of which Sir John has also posted on the Interwebby Thingy (as my son calls it):

    Brahms – Ich schwing mein Horn ins Jammertal

    Brahms – Einförmig ist der Liebe Gram (magic!!! Based on Schubert’s Organ Grinder)

    Brahms – Nänie (complete! requires a larger orchestra than the symphonies and a larger choir than the above!)

    Also on the CD but not on the web, is The Song of Fate (almost as lovely as the Song of Destiny).
    And, BTW you also get a superb performance of the the 3rd Symphony, but I bet you’ve heard that work before!

    Thanks for the Brahms. It’s playing as I write these words.

  8. Love it. With due respect, could some of the increase in diet quality come from animal tissue, yet another portion come from our mastery of fire and consuming cooked vegetation?

    In the paper Aiello and Wheeler describe two large jumps in brain size. The first they attribute for sure to the increase in meat eating because it was prior to the discovery of fire; the second they speculate may have come about because of cooking. But, remember, cooked meat is better digested than raw meat, so even cooking just meat will provide a higher quality diet.

  9. Awesome Doc! Great theory, and one that certainly makes one wonder if the reason some of our current vegetarian friends don’t “get” the lower carb notion, might be because their brains are shrinking due to their diet!!! 😉

    A bit off topic, but if you carry the “evolve because we ate meat theory” over the next few million years, you can envision a being that looks something very eeriely looking like the typical drawing of an alien!!! :0

    Thanks for a well written blog!

    -Meat only eating for the last year!!!-

  10. Excellent post, as usual. Thank you.

    Why doesn’t the ETH logic apply to other carnivores? Lions eat meat but don’t seem very smart. How do they maintain parity with Kleiber’s law?

    Lions and other carnivores obviously didn’t have the selective pressures to develop larger brains that humans did.

    1. I would think the high thermogenic effect of protein would require that lot more energy is required just for converting protein into glucose. It would increase the metabolic rate, and we still wouldn’t have enough balance energy to grow large brains.

      I think the difference between humans and pure carnivores is that we started as fruit eaters with a capacity to use starch. This allowed us to use the protein, not as fuel. We also would have preferred the fat. This carb + fat double whammy allowed us to simplify our digestion, without losing energy through thermogenesis.

      That I guess was the first jump.

      The next jump was when we started to cook, and provided us with a stable source of energy in the form of starches via baking starchy tubers/fruits/nuts, which were previously inaccessible. This reduced the pressure on us to constantly lookout for fat.

    2. This doesn’t really explain why they have a smaller brain. They do have simpler digestive system. If we use ETH, then they should have a lot more energy available. Where is the extra energy going? I believe the answer is gluconeogenesis. It is known to be pretty thermogenic.

  11. Excellent!

    It’s amazing that our primate relatives are used as evidence for our alleged vegetarian instincts whilst hominid evolution is simply ignored. The evidence for human meat eating is so overwhelming that it could be something only as contemptible as wishful thinking that compels a person to dismiss it.

    Vegetarians are free to eat like chimpanzees if they want – I’ll eat more like a neanderthal myself – but it is annoying that they falsify and mispresent evidence to justify their lifestyle choice. Why do they think they need to?

    On this point Michael (wishful thinking), have you ever read Steven Goldberg’s books? I think they’d be up your street.

    I haven’t read Goldberg’s books, but I just looked them up. You’re right. They sound right up my alley. I’ll have to order a couple.

  12. Fascinating! What is the connection between the nutritional quality of meat and a smaller digestive tract?

    Meat contains many more nutrients – including calories – per unit mass than plan foods. Since meat is vastly more nutritionally dense than vegetation, it requires a much smaller GI tract to extract the nutrients from meat.

  13. Wow, that’s amazing!

    It also reminds me of the opening scene of 2001: A Space Odyssey. The monolith teaches the ancient apes to make tools–everyone remembers that part–but the first thing they do with the tools is use them to kill a large animal and devour its meat. I wonder why Kubrick & Clarke filmed it that way.

  14. Absolutely fascinating post. Thank you!

    I’d be curious to see within-species data regarding relative sizes (and thus energy expenditure) of brain/gut. It may have been advantageous to allow for developmental differences in brain-gut ratio depending on diet…

  15. One of the best blog posts I’ve ever read. Gripping, well-written and ruthlessly logical. Amazing. Keep it up.

    Thanks. But I didn’t so much as write it as I simply explained a brilliant paper.

  16. Dear Dr. Eades:

    Evolution is a faith based theory. If you were to evaluate your conclusions from information that is science based — observable and repeatable — information, would you come to the same conclusions? And I do not mean only in relation to this article but in relation to all that you conclude about how to eat. It would give validity to your conclusions for those of us whose faith is based on the literal Word of God.

    It might be interesting to note that the Bible teaches that man was created on the 6th day in God’s image, man began as a vegetarian, not eating meat until after the flood.

    Just thought I would suggest this without any expectations of your consideration.

    I do enjoy some of your newsletters. Thank you for all the work you do and share.

    Thanks for writing.

    1. Forgive me if I’m wrong, but isn’t today “after the flood”?
      And didn’t Abel offer meat to God before the flood, meat that God prefered to Cain’s gluten grains?

  17. Thank you for this amazing post. I’ve forwarded it to all my carnivorous, LC friends. I had heard of Kleiber’s Law from a book called ‘Simplexity’ by Jeffrey Kluger. Have you read that? I loved it. Thanks a trillion for all your work.

    Haven’t read ‘Simplexity,’ but it looks like my kind of book. Thanks for the recommendation.

  18. If it was meat consumption alone that lead to our increased brain size, then why didn’t other carnivores, especially cats, also develop large brains? Lierre Keith posits in “The Vegetarian Myth” that it is man’s unique ability to crush our prey’s skull and get access to the fatty brain (mostly saturated fat at that) which ultimately allowed our human ancestors to develop their own large brains. BTW, I love this book! Thanks for recommending it.

    The big cats developed through a different line than we did. They may not have had the selection pressures we did – given our relatively small bodies and relative lack of strength and speed – to grow a large brain.

    1. The difference between them and us, is that we don’t convert much protein into glucose, which is very thermogenic, but utilize fat and carbohydrates directly to obtain fuel, which can be used as fuel directly. We were in a unique position to do this because of our opposable thumbs allowed us to use tools to crack open skulls and bones to get at the fat, and we had a primate heritage which allowed us to use carbs from tubers/fruits/nuts etc.

    2. Because man is the only carnivore that doesn’t set aside glucose to make vitamin C. This gives an extra 10g glucose daily (or more) to run the brain in times of famine.
      This is a handicap to most primates, and God knows humans have suffered enough for it, but it may have been our trump card when we started growing bigger brains.

  19. Perhaps you can shed some light on the issue of dairy consumption, in light of these amazing discoveries. Specifically, i’m interested in where the disconnect is between the approach of the Paleolithic diet regime and the approach of the WAPF. The former, of course, restricts dairy entirely (in my understanding), arguing that we’d have never consumed dairy in our prehistoric state, whereas the latter vehemently champions the incorporation of raw dairy only into the diet, claiming that whole raw milk is a “perfect food”. If memory serves, some nomadic herding groups have consumed milk as a staple and many have consumed various raw, fermented dairy foods (Dr. Eades, I believe you referenced Mongol usage of yogurt at one time…), but none in the paleolithic era.

    It’s my understanding that for most low-carb dieters, this issue is moot, as even whole milk is a problem because of the quantity of carbs. I’ve read some conflicting ideas on the carb count for yogurt and kefir, but it appears these forms of milk may have a diminished carb count and thus would be acceptable (and probably more digestible). Is this true? If lactose is the indigestible component of milk, the lactose-consuming bacteria present in fermenting milk should solve the indigestibility issue. The question for me, then, is DOES this solve the sugar issue, as some (Dr. Goldberg, etc) claim?

    It does not totally solve the sugar issue. Lactose (milk sugar) is a disaccharide – a sugar composed of two sugar molecules – made of galactose and glucose. Both galactose and glucose are sugars that are easily digested, but not when hooked together as lactose. All of us can break down lactose to its two simple sugars when we are young, but many lose that ability with age. If we can’t break down lactose to galactose and glucose, then we can’t absorb it. If we can’t absorb it, it continues down the GI tract and provides food for bacteria, which produce gas, bloating and diarrhea as a consequence. Some of the lactose is converted to acid in the yogurt-making process, leaving less for the GI tract to deal with. Yogurt contains less sugar than the amount of milk used to make it, but all the sugar is not gone. You still have to account for some.

  20. “I haven’t read Goldberg’s books, but I just looked them up. You’re right. They sound right up my alley. I’ll have to order a couple.”

    Great. You’ll like them – I promise.

    Thanks for the blog. I learn a lot.

  21. Regarding what Stefan said about the opening of 2001: A Space Odessy. I wonder if tools weren’t developed to kill other animals so much as to kill each other, first.

  22. While I am a firm believer in that we evolved eating meat, here is the McDougall version on why we evolved as starch eaters: ,

    “Proponents of meat-based diets preach that the introduction of meat into the human diet was responsible for the evolutionary development of the human brain. One of this study’s principle authors said this theory is improbable. Nathaniel Dominy pointed out, “Even when you look at modern human hunter-gatherers, meat is a relatively small fraction of their diet. They cooperate with language, use nets; they have poisoned arrows, even, and still it’s not that easy to hunt meat. To think that, two to four million years ago, a small-brained, awkwardly bipedal animal could efficiently acquire meat, even by scavenging, just doesn’t make a whole lot of sense.”

    The paragraph about the modern human hunter-gatherers is simply not true. Here is a link to a paper in the American Journal of Clinical Nutrition, the world’s most prestigious nutritional scientific journal showing that modern hunter-gatherers get on average 65 percent of their calories from food of animal origin.

  23. Hi Mike – thanks for the heads-up to your I’ve Been Tagged post : quite a history.

    Reminds me that April last I came across “Discover Your Strengths” by Marcus Birmingham from the Gallup Organization. It’s an approach now used in Human Resources(HR) management to analyse what are termed Strengths – really Talents or Bents – rather than physiological or intellectual skills. It may also be used in Career Advice. Have you come across it?

    Having bought & read the book I found it had a code which I could use on the StrengthsFinder site to take a questionnaire. I was then given my 5 Signature Themes. These themes explained many of the successes and failures in my career as well as many of my approaches to Life, the Universe & Everything. I was impressed. (They invited me to pay USD 500 for a telephone consult to explore my next 10 themes, but I declined!)

    My take is, if you have not come across it, you would find it interesting; after all you recommended Glasser’s Choice Theory!

    Google “strengthsfinder” if you want to follow it up.

    BTW what did you think of Jonah Lehrer’s hypothesis on placebo effect in chapter five of The Decisive Moment? I liked it.

    Any chance of a literary post – when you have a leisure moment?


    I’ll take a look at the StrengthFinders site. I did enjoy Lehrer’s book from beginning to end.

    Whenever I get a leisure moment, I’ll see if I can crank out a literary post.

  24. @ Dr. Mike

    I already submited this story to Digg. You can see your Digg page here:

    Unfortunately, Diggers seem to side with the vegetarians on this issue, according to the responses in other vegetarian stories. I bet they all use Apple computers too!

    I use an Apple (Mac), and I certainly no vegetarian.

    I just realized that I used to have a Digg button on my blog, but it vanished during the redo.

  25. The paper also explains a fallacy often put forward by Natural Hygienists, that carnivores have short GI tracts because “they must get rid of the meat quickly before it putrefies”. No, it’s because GI tracts are metabolically expensive and you don’t evolve a longer GI tract than you have to. This sort of scientific rigor is what attracts me to the paleo/primal diet theories, they just make SENSE!

    Yes, that nonsense about meat putrefying sets my teeth on edge every time I see it.

  26. Fantastic post; glad I was able to d/l the journal article from Scrib’d to digest further. Yet another tool to counter the veggie folks’ assertions that we all started out as plant eaters (well, we did, but that was long ago, when we resembled our primate cousins).

    I had seen comparisons of modern herbivores to human GI tracts (i.e., sheep vs. human in one of your books), but had never thought to look at hominid evolution. It is interesting that our emphasis on carbohydrates has led to many of us adopting a faux-gorilla profile.

    Yes, indeed. I was going to add that to the post, but decided not to because (a the post was going on forever as it was, and (b I didn’t want to insert my opinion into the piece.

  27. Long time reader, first time commenter. Great article and it makes a lot of sense.

    I am apparently the third to pick out carnivorous cats as making this theory questionable. Even though you answered the question earlier regarding cats I am still a bit unsatisfied. Cats may not have had the same selective pressures, but they do have small(er) GI tracts from what I hear. If that is the case then either Kleiber’s law is violated and they have a lower metabolic rate OR there is some other metabolically expensive tissue that makes up for it (instead of brain matter). Is it their musculature that is larger in proportion to their bodies that grew as a result of their selection pressure? I would love to see the chart of a big cat’s actual and expected as in the organ weight chart above. Muscle is my guess but I am not sure since you mentioned it isn’t much of a contributor. I would be curious as to your answer.

    Great stuff and keep up the good work,

    Jeff(meat and paleoish low-carb eater)

    I don’t have the data on the big cats. The Expensive-Tissue Hypothesis was written to address the rapid increase in human brain size. We are a totally different genus and species from lions and tigers, so what applies to us doesn’t necessarily apply to them. They are on the Kleiber line, but I don’t know what makes up the difference anatomically between their small GI tracts and brain size. Obviously something does – I just don’t know what because I’ve never studied it. Lions do have a considerably larger muscle mass on a per body unit basis than humans, so maybe some of it is there. Since they are in a different genus, maybe their hearts and/or kidneys are larger as well. Aiello and Wheeler compared us to primates, since that is the line from which we descended.

    1. I think the clue is nucleogenesis. I think the problem is that the surface area of an animal can only emit so much energy. You may be able to get as much energy as you want. The carnivores being dependent on nucleogenesis must convert a lot of their protein into glucose, which is a very thermogenic process. This I think will explain the lack of available energy for them to grow larger brains.

  28. I would like to comment on the post of Charlie Gayle concerning possible bad effects from eating pemmican. About the time when these men became ill from eating pemmican the nutritionists became increasingly influential. The nutritionists thought that the addition of carbohydrates would make pemmican more nutritious. The pemmican in question may not have been the traditional pemmican of earlier times. Barry Groves in his book “Trick and Treat” believes that the nutritionists might be primarily responsible for the deaths of Captain Scott and his South Polar expedition team in 1912. They were carrying food with a low energy density. Pemmican is food with almost the highest energy density possible so that a very large amount of calories can be carried without any replenishment.

  29. You should add a “share on facebook” link to your blog entries:

    I don’t even have a Facebook account. I was going to do it, but Tim Ferriss told me it was a bigger PITA than it was worth. All I need is some other way for people to send me emails and messages that I would feel obliged to answer.

  30. Thanks for the great post!

    One thing that never seems to be mentioned in the carnivore vs herbivore discussion is that humans probably ate of lot of bugs and worms–some still do. Good protein but not difficult to hunt.

    True. That was addressed in the AJCN paper I linked to in an earlier comment.

  31. Great post! Echoing the same praises as other commenters. As a nonscientist, I probably would not have understood this without a clear explanation like this. Many thanks, Dr. Mike.

    Glad you enjoyed it.

  32. Back in my anthropology days at school we were lectured about the importance of meat to human evolution, but I don’t recall that our professor talked so much about the GI tract as the quality of the diet, and the chewability. If I remember correctly (not guaranteed!), as the diet grew finer and contained less roughage and coarse plant fibers, there was a corresponding decrease in tooth and jaw size, but the attachment sites on the skull for the jaw musculature also decreased, which allowed the intracranial capacity to increase.

    This could be a potential explanation for why other carnivores such as the large cats haven’t evolved human-like large brains – they need their massive jaw musculature for hunting and breaking apart carcasses.


    Interesting idea, but, as Aiello and Wheeler warned in the ECT, you’ve got to be careful deriving theories from specific anatomical points without looking at the total picture. But, could be the difference between us and the big cats.

  33. Hi Dr. Eades,

    Very nice. But there’s the issue of cooked starchy tubers– those are also a high-quality food in terms of calories per unit fiber and ease of digestibility. The brain is a glucose hungry organ after all. It doesn’t use fatty acids like the other organs, and will only use ketones if there’s no glucose around. I’d be surprised if cooked starch didn’t play a role in human brain evolution as well. It’s one of the most commonly eaten foods by contemporary HGs.

    I agree. And the authors of the paper discussed cooked tubers. But the brain took a growth spurt before the advent of cooking, so at least that much of the increased cranial capacity came from meat eating. I don’t know how much of primitive man’s caloric intake came from starch and how much from animal sources, but from Cordain’s classic troll through the Ethnographic Atlas (a database of all contemporary hunter/gatherers), the average contemporary hunter/gatherer got 65% of calories from animals and 35% of calories from plant sources.

  34. I had to look up “ineluctable.” To make sure I’d understand it, I had a burger patty first.

    The guy thinks he’s a comedian.:-)

  35. @Obvy

    The carb content of even unsweetened plain yogurt is around 20g per cup because of the remaining lactose in the milk that it is derived from. Interestingly, my local grocery chain carries their own brand of low carb yogurt that is only 3g of carb per cup. To do this, they have replaced the milk with water, milk protein, whey protein and cream. They use small bits of fruit and Sucralose to flavor and sweeten it. It also contains active bacteria cultures. It’s quite good.

  36. @JD

    Johanson makes the point in his book: “Lucy: The Beginnings of Humankind” that the most primitive of our human ancestors, while being small of stature and cranial size, had pelvises nearly identical to modern humans, and thus had our same bipedal ambulation skills. He dispelled the notion that there was ever a hominid that was “awkwardly bipedal.” Given this and the fact that non-human small brained carnivores are quite adept at hunting, it would be a mistake to assume that early hominids were not.

  37. Excellent blog Michael. Shouldn’t the corollary be true ie do small headed people have larger hearts, gi’s or whatever. Are the record holders of say the 5000 metres more small headed, lb for lb, then there fellow competitors due to perhaps their larger hearts?

    I don’t know that the Kleiber line is accurate enough to apply to individuals vs applying it to groups.

  38. @Allen and Dr. Eades

    I have, in the past, made extremely sour aged kefir that, i’ve heard anecdotally, breaks down a greater quantity of lactose than yogurt. Dr. Goldberg in “Four Corners Diet” asserts that there are four grams carbs remaining in yogurt after culturing and even less in sour kefir. He claims that he has tested this himself. HOWEVER, if he is correct, and if those four g carbs are lactose, could the remaining sugar be present as galactose and glucose and still negatively impact blood sugar?

    I’m trying to assess whether or not it is possible to include kefir and, to a lesser extent, whole plain yogurt in a low carb diet. I’m just not sure how to “count” the carbs in these foods.

  39. I am at least glad that they didn’t just go rollicking down that much loved (of anthropologists, anyway) blind alley of “big brains are necessary to be Great Hunters”. Phtaah. However, big brains MAY just get the girl… (I like that hypothesis, myself. I’m a female that likes smart men that like smart women, but that also bring home the bacon ;->) But we aren’t discussing WHY the big brain, just the possible HOW of the big brain.

    There is indeed, food for thought here. (Forgive the pun. Never mind, I love puns. I never miss the O’Henry pun-off in the Great Republic’s capital city. The highest expression of the lowest form of humor… Humor for the masses.) Thanks for giving us this tasty new morsel to chew on! (I can’t HELP myself!)


    Glad you enjoyed it, er, at least I think you enjoyed it. 🙂

  40. Superb article.

    I have noticed in this post and in most others a disturbing number of typos and other mistakes. I thus volunteer, as an experience proofreader, author and book collaborator, to proof your future postings. In fact, I’d be honored.

    Thanks again for such outstanding and interesting pieces. Your content puts most medically oriented blogs to shame.

    Do like everyone else does and proof them after they’re up. I’ll be happy to make all the changes as you find the errors.

  41. The question “what about big cats, and wolves keeps coming up”… I would say in the mammalian kingdom, it is fairly obvious that dogs and cats have more intelligence than guinea pigs, and chipmunks etc… Ditto dolphins and whales. Omnivores like chimpanzees, bears, minks, ferrets, foxes, martins, even rats, seem to have exceptional problem solving skills when compared to a deer or a bovine. Beyond that, it is obvious that the human/primate genus, would be leaps and bounds past other mammals without meat, but when you add that to the equation you get something extraordinary: a human being.

    Excellent article!

  42. Tim was right about Facebook: PITA! I have no idea how you even have time for these amazing posts – and responding to comments! I am toasting your “expensive tissue,” and am glad you are feeding it meat!

    Thanks. Meat eating is the only way I could survive the constant battle.

  43. Great post, I had heard of the ETH but this was a great review of it. Still waiting with baited breath (yesterday was sashimi day and dessert was ikura) for an update on your world-changing project, hope it’s going well. But no pressure, eh. 😉

    Here’s another book for your spare time, if you haven’t read it yet: _Primal Body, Primal Mind_ by Nora Gedgaudas. The Drs. Eades are quoted in a couple of places. There’s a fair amount of convergence with PP, GCBC, Paleo but also chapters on leptin, mTOR (she appears to be a fan of VLC CHRONish protein restriction) and the relationship of nutrition to specific psychiatric disorders which I hadn’t seen in that much depth before. Good writing, lots of references, the editing could have been better but not bad for what appears to be a self-published work.

    I think I got this book somewhere along the way, but haven’t read it yet. I’ll dig it out and take a look.

    The very next post will be the revelation of what we’ve been working on. I do think it will be world changing in a way. But we’ll have to wait to see. God knows, we’ve spent enough time on it.

  44. Thanks Dr. Eades. This really answered some of the remaining questions I’ve been asked, but have yet been unable to answer, regarding our cooked meat eating origins. Despite how this may sound, I’m not actually discussing religion here but merely being a bit tongue in cheek (don’t think to ill of me) . . .

    In response to Phillis’ comment about how we were biblically vegetarian, when Adam and Eve stray by eating from the tree of knowledge, God says:

    In the sweat of thy face shalt thou eat bread, till thou return unto the ground (Genesis 3:19, KJV).

    Essentially, they are condemned to bread! Even in the old days it was known that agriculture was essentially a punishment.

    I don’t think ill of you. I’ve used that very verse myself.

  45. Another great article, Dr. Eades. In all honesty, the only proof I need that we are meat eaters is to watch my three year old attack a plate of yummy, greasy, bacon…she is a paleo baby and has the big brain and straight teeth to show for it. I had a friend who was a vegan and raised her child as such. We are no longer friends because (in her words) I’m an evil animal eater. LOL. Her child was ALWAYS sick and cranky, and was allergic to everything from peanuts to wheat. At one year old, the baby didn’t even have the muscle mass to pull herself up to standing on the sofa, meanwhile my kid was running around the house on her sturdy legs at 10 months. I think its such a shame, when I see other toddlers drinking skim milk and eating crackers. Those poor babies are just starved for fat and nutrition.

    I am also so glad to have yet ANOTHER article to show people how I keep my hourglass figure while eating chili burgers with extra cheese (hold the bun) and meatloaf! Vegan friend, last I saw, still looked pregnant….sometimes the answer is right in front of you, but you still can’t see it!

  46. Thank you for such an enlightening article. It’s funny though. Back in the early 1980s I took a number of grad courses in human paleontology, just for fun (we did flint knapping and everything!). I was so taken with everything I read, I ended up acing every test, much to the chagrin of the paleontology major who sat next to me who was only getting Cs.

    Anyway, I remember reading and talking about this theory back then, so it’s not new to me. I’ve always “known” that the brain is an “expensive” organ and the only way to “pay” for it is to give it the highest-quality food available … meat. Never a doubt in my mind. I’m glad to see this theory getting the light of day again.

    Hmmm. I wonder what made it fall out of favor for a while. Regardles, glad it’s back and glad you posted on it!

    EXCELLENT post!

  47. Dr. Eades: I’ve been a fan of yours since discovering the diet issues in “Good Calories, Bad Calories,” only last October — regrettably much too late in my 6 decades; however, your advice has worked wonders in my health (lost about 4 inches of visceral fat so far, not to mention other improvements). THANK YOU very much. I want you to know that your focus on science and proper epistemological methods is much appreciated by this layman, and especially that you translate the science issues to layman terms. May you and yours keep up the good work for many years to come. As Spock would say: “Live long and prosper.”
    — Rob McVey, Markham, Ont.

    Thanks very much.

  48. Regarding the bible, the whole bit about Cain the farmer killing his brother Abel the shepard, was his jealousy that god accepted the sacrifice of animals from Abel but not the produce from Cain! So what do we take from that?

    It’s pretty obvious to me.

  49. Nice post (if you are a fan of anthropology). You are totally backed up in the thought that we evolved a larger brain by eating meat — there seems to be almost no question of this. I hope the intelligent readers of this blog realize that just because we evolved eating a particular food (ie, meat), this does not mean automatically that eating meat is optimal for longevity. Eating some meat and animal fat is almost certainly longevity promoting, the question is in how much? I’m very happy though that your article dismisses the typical vegan notion that we are not compatible with eating meat, which is a ridiculous notion.

  50. Something I have never seen talked about on these forums is possibly the ‘elephant in the room ‘ re human evolution.

    If hunger were undoubtedly our ancestors’ constant companion, and once early human groups developed, then a form of tribalism would have ensued.
    There would have been constant danger from other larger predators, but probably the greatest danger would have been neighbouring hostile human groups..competiing for scarce resources.
    Up until quite recently cannibalism was common in parts of the world, and an accepted part of both diet and a consequence of hostilities. I have read where it is not unheard of in some chimpanzee groups.

    I wonder how this might have affected human dietary evolution?

    If true, it probably made us smarter since we had to out think other humans and not just animals. Would have made our brains grow fast.

  51. Hey Mike, I’m glad you decided to post about this article. I had to read it several times to understand certain parts of it and I could see how the journal may have decided that it was too technical… On the other hand, that’s why they have other people who read through and write a summary (though not as thorough as your presentation here), highlighting their ‘masterpieces’. As you said, chances are it wasn’t how technical the article was but how controversial. I told you your readers would love it! 🙂

    Anyway, with respect to brains getting larger, a little after Protein Power LifePlan was published, the book “The Omega-3 Connection” came out, written by Andrew Stoll. Among other things, in a chapter about evolution, he explains some of the theories surrounding the enlargement of the brain but his take in on fat consumption, perhaps over other nutrients. After reading Aiello’s article (and aided by your very elegant presentation of it), it rather easy, at least for me, to see how eating more fat could have resulted in increased brain size; the food that was most available where it all began for us humans was fish and shellfish… animal foodstuffs that contain plenty of protein and fat.

    You wrote above about muscle mass not increasing metabolism, however, muscle is metabolically more active than fat is it not? I mean, because muscle is always ‘hungry’ for energy to maintain its mass, hence the recommendation of getting our muscles in good shape so their ‘hunger’ for energy can be supplied by our stored fat. Even without a metabolic rate as high as the brain, perhaps muscle contribution to overall metabolic rate shouldn’t be entirely discounted. Your recommendations on exercise since Protein Power to ‘The Cure’, seem to emphasize the fact that muscles contribute a great deal with the way we ‘dispose’ (in a good way) of stored fat since muscles are avid users of fatty acids as an alternative fuel for their metabolism, at least those muscles that work through aerobic metabolism. Any thoughts on this?

    Thanks again for this elegant presentation of Aiello’s article!

    Since I knew you had read the Aiello article, I was keen to get your take on my presentation of it. I’m glad you liked it.

    There is no question that muscle is metabolically active, but it’s just not as much as you would imaging. I found this out when I wanted to do a piece a few years ago about how many extra calories one would burn by packing on a few pounds of muscle. I went to the primo exercise physiology text and looked up the metabolic rate for muscle and did the calculations and discovered that an extra pound of muscle burns just a few extra calories. I don’t remember how many extra, but I do remember that I was stunned that it was so few. I redid the calculations several times (including rechecking the figures in the book and going to other sources to confirm the factors) because I simply couldn’t believe what I was seeing. Try it yourself and let me know what you find.

  52. @Obvy re: yogurt & low carb

    Two words: Go Greek

    I like Fage’s Total.

    @ Dr Mike – Thanks are inadequate expression of my appreciation for all the great work you do, especially this blog. So I’ll just have to keep buying more of your books.

    Thanks for the kind words. I really appreciate them.

  53. @LCforevah: My take on the Cain and Abel story is that it was a tale of two cultures. Pastoral herders vs the Neolithic farmers. Told from the point of view of the herders, it is teaching story about what is acceptable for sacrifice…. meat and blood. Not plants.

  54. Do I have a few jokes about vegetarians coming up!

    I always said carbohydrate made us fat, sick, weak and stupid. Mike, don’t let the veggies read this or their brains won’t be able to handle it! I’m happy to be a carnivore, it allows me to surpass all my vegetarian friends in intellectual endeavors! You know what vegetarians say, if you can’t be smart, at least be politically correct! That last one made me laugh out loud.

    Thanks Dr Eades, I enjoyed that post.

  55. I’ve always felt that this was the case, thanks for giving me the ammo I need!!

    “Yes, that nonsense about meat putrefying sets my teeth on edge every time I see it.”

    Me too!! Also when people talk about colon “cleansing”!

    @AJ…Another thing that “sets my teeth on edge” is that pregnant women are being told to keep fat as low as possible! And 2 yr old being changed to low fat! Do these people not understand brain development needs fat??

    Luckily, my own daughter (who just got married) HAS listened to what I’ve preached and is currently trying to educate her friends!

  56. – – – Tom Naughton, 22. September 2009, 10:23
    – – – I had to look up “ineluctable.” To make sure I’d understand it, I had a burger patty first.

    Words like that have a magnetic effect on the author’s eyes. When re-reading and editing, as he closer to the word, his eyes accelerate and skip right past the blatant typos earlier in the sentence so that he may stop and marvel at his creative patois.

    Fascinating post Doc. Thanks! (Plenty of typos still though, keep editing.)

    Hey Todd–

    You wrote “Plenty of typos still though, keep editing.” Are you talking about my writing or yours?

    See above:

    “When re-reading and editing, as he closer to the word…”

    As he closer to the word?

    I read something once about people living in glass houses, but I can’t remember the rest of the quote. 🙂

    I’ll always cheerfully admit to and fix any typos I make. When I write these things, I’m writing like a maniac, and when I’m through, I go back through, sort of. I’m so ready to have it up and be done with it that I don’t do the thorough re-read and edit that I should.

    I have to count on my faithful readers to point these typos out to me.

    1. “People who live in glass houses should not cast the first stone until they have removed the beam that is in their own eye.”

  57. I suspect we’ve begun an evolutionary divergence whereby vegetarians will develop longer intestinal tracts at the expense of brain matter, eventually becoming a separate species.

    When they do become a separate species, I wonder if they’ll taste like chicken.

  58. Another first time poster but long time reader and follower.

    Very interesting correlation between eating meat and brain growth. However I think that environment must have played important part as well. When I was 13 y.o. I broke my leg. It was put in cast for about six weeks and once the cast was off I have noticed that the injured leg lost almost half of the muscle comparing to the non-injured leg. I assume that due to that limb being immobile the body’s energy preservation system kicked in and reduced the size of unused muscle tissue. Thinking of our ancestors when they started eating meat their body realised that it did not need same amount of energy for digesting meat as it was needed for plant food. So naturally there digestive system got smaller in size. The question is why was that extra energy diverted to brain and not to some other part of the body and would our brains grow if the meat was easily obtainable food source? Physically comparing to other animals such as big cats we are not that impressive. As we lived in groups killing or retaking already killed larger animal was necessary to survive. This brought us in face to face with other predators who competed for the same food source. So the humans had to create strategy and develop the tools to effectively obtain meat without becoming a diner for some other predator. Demand for meat created the need for thinking and that bit of extra energy that was previously used for digestion was diverted to the brain and presto, over the two million years we become most successful predators on this planet.

    The point of “The Expensive-Tissue Hypothesis” is that we’ll probably never know the ‘why’ but we can make a pretty good guess at ‘how’ our brains were enabled to enlarge.

  59. I had to look up “ineluctable.” To make sure I’d understand it, I had a burger patty first.

    Tom, at least you got it with the a burger patty, it took me a whole lot more than that!

    Dr Mike, i could never understand the transition of pirmates to monkeys. If there is a forward progression, how come there is no backwards movements in nature? In other words what would take us humans to become monkeys again, vegetarian diet ,lol oops did I just say that?

    I don’t think it can go backwards.

  60. Interesting, since vegetarians believe that not eating meat is a more cerebral and highly evolved.

    I do think humans evolved to eat meat, but as to why we acquired the larger brain is a little like which came first, the chicken or the egg. Is the larger brain, smaller gut and shorter digestive track a direct result of eating meat, or was it a necessary outcome of being physically ill-equipped as hunters; not having speed or razor sharp teeth and claws to rip apart flesh. The compensation became a larger brain and thus, hunting smarter.

    You say there were other primate groups that socialized and hunted, but whose brains had remained small; Why would this be if it was simply a matter of eating meat? Is it possible that a particular colony due to a certain hardship, possessed a little more will,,, determination,,, consciousness, and as a result were rewarded with a little more brain… a little less gut.

  61. you know what convinced me to leave my vegetarian lifestyle and eat meat again? when i noticed that when i cooked vegetables and grains i had no reaction the cooking aromas but whenever i smelled meat cooking my mouth would immediately begin to water!

    love your blog!


  62. — You wrote “Plenty of typos still though, keep editing.” Are you talking about my writing or yours? —

    Both! My tail is firmly wedged between my legs, though it proves my point. This blog software filtered out the big smiley grin I inserted at the end of that sentence. So much for trying to be funny.

    I thought it was funny. I very seldom comment on other blogs because I don’t have time as I’m always busy dealing with comments on my own. But one day someone forwarded me a blog post that I couldn’t resist commenting on. The jerk who wrote it was so pompous (and I don’t even remember now who it was) that it made me sick. I took him to task in a comment, basically called him an idiot, and as a final flourish I pointed out a few typos he had made. Of course, when my own comment got posted, I had a bad typo in there myself. I used their for they’re. Or maybe it was the other way. I was so mortified I repressed it. And, of course, the jerk pointed it out just as I pointed yours out. So I feel your pain.

  63. — When they do become a separate species, I wonder if they’ll taste like chicken. —

    I hope so, but I suspect they’ll taste like asparagus and smell like brocolli. A defense mechanism evolved to protect them against us carnivores.

  64. “I thus volunteer, as an experience proofreader, author and book collaborator, to proof your future postings.”

    Roger, now I must volunteer to proof your proofreading as I am an experienced editor. 😛

  65. Thanks for the comments Mike. You know I had to try to check some numbers myself… though not very thoroughly tonight. I did find, however, a couple of references that suggest that muscle metabolic rate is indeed ‘not all that’, and it may be overestimated in most cases. In one reference (Am J Clin Nutr 2006;84:475–82) [], Robert Wolfe suggest that “every 10-kilogram difference in lean mass translates to a difference in energy expenditure of 100 calories per day, assuming a constant rate of protein turnover.” That’s only about 10 cal/kg muscle (or ~5 cal per pound of muscle!). The other reference, a bit older (Obes Res. 2001;9:331-336) [], the authors propose a classification scheme founded on body composition level (whole-body, tissue-organ, cellular, and molecular) and related components as the resting energy expenditure predictor variables. Rather technical but if some of the equations are applied to muscle, then we find that muscle the daily metabolic rate for muscle is just about 6 calories per pound per day, not very far from Wolfe’s predictions and very low indeed!

    I can see how this could lead to the notion of ‘exercising is a waste of time’. While the increase in metabolic rate is modest at best (or right out low…), at least is higher than the metabolic rate of a similar weight of fat, which is about 2 calories per pound per day. Perhaps the lesson is that the right kind of exercise (resistance in this case, and probably more on the heavier side of weight training) improves body composition by burning more calories than fat in the hours after exercise and by preserving lean body mass while dieting for weight loss. In any case, certainly there may not be such thing as three extra pounds of lean muscle burns about 10,000 extra calories a month as I seem to remember from “Power of 10: The Once-a-Week Slow Motion Fitness Revolution”.

    I’ll still take those very few extra calories per pound of muscle if that keeps my extra fat from accumulating! 🙂

    Thanks again!

  66. With all due respect to your gorilla readers, I must say that eating meat also made the female members of our species soooo much more attractive. IMHO, of course.

  67. Very interesting post, thanks for putting up Part II.

    I think you covered my particular interest in your reply to Alex:

    @Dr Mike: “The point of “The Expensive-Tissue Hypothesis” is that we’ll probably never know the ‘why’ but we can make a pretty good guess at ‘how’ our brains were enabled to enlarge.”

    My interest is that the ‘why’ could be any combination of things in a chicken and egg sort of way.

    For example, a group of hominids could have suddenly found themselves in a niche where meat was easy to get (even with small brains) and very plentiful. After a while their digestive tracts could have shrank since there was no selective pressure for more digestive ability. This would have freed up resources for the brain to grow larger and more complex and energy hungry assuming this gave a survival/reproductive advantage.

    Or it could have gone the other way around. Some selective pressure led to larger brains (for example hunting or social drivers), but only those with more efficient digestive tracts could survive due to energy requirements, which meant the survivors gravitated towards meat eating.

    And of course it could be something in-between, co-evolving. Multiple paths result in falling on the line of ETH. I read your article twice and I don’t think I’m disagreeing with anything you said, correct me if I’m wrong.

    You’re right. The ‘why’ could be almost anything.

  68. “Do like everyone else does and proof them after they’re up. I’ll be happy to make all the changes as you find the errors.”

    Ah, Dr. Eades is much too indulgent and I’d much rather he spend the time on more productive endeavors. To those who have nothing else to do but to point out minor typos, I would suggest that you keep a scrapbook of your finds and review them from time to time to keep yourselves happy. Dr. Eades isn’t making these errors out of ignorance; given the substance of the posts, who cares if he misses a letter as his fingers fly over the keys? Give it a rest.

    I really don’t mind. I would much rather have my typos pointed out so that I can fix them. That’s the nice thing about a blog post – it can be corrected.

  69. Actually–and I need to start taking notes when I run across this stuff, I can’t remember the source–cats are held to be the next most-intelligent animal after primates. By whom, I really don’t know, and I don’t know how they measure it, but generally, carnivores seem the more intelligent vertebrates overall.

    It could be that because cats don’t have opposable thumbs and can’t walk upright, that limits their options insofar as how much neato stuff they can do with their intelligence. But believe me, they do think. Even housecats are very, very smart. Mine almost scare me sometimes.

  70. Oh, and a few comments up, someone posits that we could have found an easy source of meat at some point and then selected for smaller guts afterward. It is thought in certain circles that proto-humans went from bug-eating to scavenging kills at some point. I’m not sure how that would work; don’t lions eat up just about every part of the critters they down, or do they leave leftovers? We’re built for picking bugs apart, not for taking meat off bones, so maybe our first tools were meant for bone-scraping and then we figured out they worked like lions’ claws. I don’t know, but it’s an interesting idea.

  71. Vadim:

    “Dr Mike, i could never understand the transition of pirmates to monkeys. If there is a forward progression, how come there is no backwards movements in nature?”

    There are no forward or backward movements in evolution. A gene mutates, the mutation doesn’t kill the organism before reproduction occurs, and presto, you have a new variation. It’s not an “improvement,” it’s not a “step down,” it just… is.

    Only some primates evolved into monkeys. Others evolved into lemurs and apes and so on. They all just sort of branched off in different directions–in the sense that reproduction *does* have a direction and you can never go home again. Apes were never monkeys–they were always two different groups. We’re apes too.

    I don’t remember how it used to be classified but these days I think our order is divvied up into “dry-nose” and “wet-nose” primates. Apes are dry-noses. I don’t know why. Scientists are weird.

  72. Hey, Dr. Mike, I just watched the Elaine Morgan talk — at around 9:30 in, she explains why humans are the only humans with subcutaneous fat (other primates — and middle-aged humans who haven’t read your new book — store their fat around their visceral organs.)

  73. The South Sea Islanders used to refer to the product of a raid against another island as “long pig”.

    I read this in a book at the of eight called The Coral Island by R M Ballantyne. The hero was a boy called Ralph who knew enough to save his younger companions with milk from green coconut and being able to build a raft. It was a schoolboy Robinson Crusoe.

    As a result I built platforms in trees, became a river swimmer and eventually relived one of Ralph’s experiences when I dived in the Caribbean!

    The other South Sea survival nugget I picked up while a young book omnivore came from The Kon-Tiki Expedition in which the raft crew began to catch fish and assuaged their thirst from the salt free fish liquor in a period when they had not replenished their water supply from rain. They also ate their fish raw, and as far as I know ingestion of fish is not improved by cooking. I notice that the ETH paper did not make any reference to fish eating or the Aquatic Ape hypothesis.

    I have never forgotten “long pig”!
    Don’t think a vegan would taste like beef until (s)he evolve a rumen and become a true herbivore.

  74. I’m curious about how we get nutrients from vegetables. A big part of the cell walls in vegetables is cellulose that we can’t break down. But we still can get some nutrients from the veggies. Is this because of the cell wall not being 100% cellulose? But if we can “open up” plant cells to get the nutrients inside, how come unchewed peas and corn get straight through the GI intact?

    Cooking helps. It’s difficult to get a lot of nutrients without cooking. Some are available, but not as many as after cooking.

  75. Thank you . I had come across references to the notion of energy conservation/ brain size before but never really understood it. Kleiber is new to me. Now a light bulb has gone on in what passes for my brain.

    Possibly related to this (and where I first came across the notion) is the human inability to manufacture
    vitamin C. Again another energy exchange.

    Eating meat that has vitamin c in it (nearly all animals produce their own) would suffice for hominid needs.
    Not having to manufacture vitamin c is energy conservation.

    Culturally it may have some bearing on our typical aversion to eating carnivores and cannibalism.

    As one of my peasant neighbours comments “Actually I really am a vegetarian, its just that I prefer my vegetables processed into meat before I eat my greens.”

  76. Dr Mike:

    I am wondering if you have heard about a exciting study being conducted by Ohio State University called the “Global History of Health Project”. You can read about it here:

    A quote from the site: “This project creates three large databases to reinterpret the history of human health in Europe from the late Paleolithic era to the early twentieth century. During this period, human health and welfare were transformed enormously by the transition from foraging to farming; the rise of cities and complex forms of social and political organization; European colonization; and industrialization. With a trans-Atlantic network of collaborators, we will undertake large-scale comparative studies of the causes and health consequences of these and other dramatic changes in arrangements for work, living, and human interaction”

    A smaller study has already been conducted, and a book is available (see the site for details).

    Interesting. I hadn’t heard of this. Thanks for the link.

  77. Even if it’s less of a metabolic advantage than we all thought, I’ll take the smaller volume from muscle mass over the blobs of fat any day. Besides, a certain amount of fitness allows us to face the challenges of daily life; muscle isn’t just smaller, it’s useful.

  78. >Dr Mike, i could never understand the transition of pirmates to monkeys. If there is a forward progression, how come there is no backwards movements in nature? In other words what would take us humans to become monkeys again, vegetarian diet ,lol oops did I just say that?

    >>I don’t think it can go backwards.

    Isn’t it just a case of usefulness versus uselessness? If a mutation provides an advantage, it tends to stick. If that once-advantage ends, the mutation can atrophy. I’m pretty sure that there are species that “lost” their eyes, for instance, when they became dark-places dwellers. No doubt parts of our bodies have devolved over the ages, too.

  79. Mea culpa, Katy and the others who noticed my gaffe. I didn’t say I could type or write well myself, just that I could find mistakes in others’ writing. But that’s what happens when you don’t proof your own work…

    As I have learned over and over.

  80. Here’s a question: if muscle isn’t as strong a calorie burner as previously thought, can we lose weight by exercising our brains? On days when I’ve spent several hours writing (hard brain work!) I’ve often thought anecdotally that I saw a reaction the next day on the scale.
    Crazy? Any thoughts?

    If this could be proven significant it could be world changing indeed!

    Hmmm. Would be interesting to check out. Are most heavy thinkers thin or fat or is there a correlation. First thing to do would be an observational study to set the hypothesis.

  81. Dr. Mike — thanks so much for such a valuable resource. My husband and I are avid followers of the PPLP approach, and I read (and re-read) your blog faithfully. I can’t tell you how much I’ve learned from your thoughtful and insightful writings.

    Now to a specific question. Yesterday a small blurb appeared in the lifestyle section of our daily paper (the Toronto Star) covering the press release of a new study from UT Southwestern Medical Center here: This one has me baffled. Some of the statements seem to run contrary to what I’ve read in your writings (and others).

    Such as: “Findings from a new UT Southwestern Medical Center study suggest that fat from certain foods we eat makes its way to the brain. Once there, the fat molecules cause the brain to send messages to the body’s cells, warning them to ignore the appetite-suppressing signals from leptin and insulin, hormones involved in weight regulation.”

    And: “Though scientists have known that eating a high-fat diet can cause insulin resistance, little has been known about the mechanism that triggers this resistance or whether specific types of fat are more likely to cause increased insulin resistance.”

    Finally: “Though scientists have known that eating a high-fat diet can cause insulin resistance, little has been known about the mechanism that triggers this resistance or whether specific types of fat are more likely to cause increased insulin resistance.”

    Of course, I could be completely misunderstanding this press release, even though it presumably is targeted at lay readers rather than at scientists. Is this one of those dreaded “observational” studies from which conclusions are being incorrectly drawn? Is something else going on here?

    Thanks for any insights — Pauline

    This study involved injecting different types of fat directly into the brains of laboratory animals. Not a lot that one can conclude from the data when applied to humans who eat their fat, which makes it way through the GI tract and the blood before it gets to the brain. Big difference between that and injecting it directly in. Here’s a post I did along similar lines that is much more reflective of what really happens.

  82. I checked out your drawings and had to comment on how nice they are. I was trained as a portrait artist so I especially appreciate them. Although it is not uncommon for creative people to have interest and talent in more than one creative field, it is rare to find someone with real talent in each field; I have met many people who delve in art, writing and music, but not really talented in all 3. I have met only one person who was exceptionally talented as an artist, writer and musician. With your exceptional talent in art and writing; and interest in music, I am surprised you have never pursued music more, like take up an instrument. Instead, you have put a lot of effort into interest such as searching for buried treasure and disappearing from charging bulls (fascinating). I think the voice in your head was saying ‘musician’… not ‘magician’. 🙂

    I do play the guitar, banjo, and violin. But not well. At least not as well as I draw and sculp. I love music, but I didn’t grow up in a musical family. We didn’t have a stereo system or even a record player until I was a junior in high school. My guitar and banjo skills are self taught, but I had some formal training on the violin. Come to think of it, though, my art skills were all self taught as well.

  83. @Elizabeth, everything you said is true and a great anthropological explanation. But the Genesis story is only of one culture, and across time, cultures and geography, every where you go on this planet, the correct sacrifice to a god has almost always been meat. I think this speaks to its value to human life everywhere as opposed to the relative lesser value of produce.

  84. Hi Dr. Mike,

    Have you read “Catching Fire: How Cooking Made Us Human” by Richard Wrangham? Seems like a book that could expound on your post.

    I have read it.

  85. “Dr Mike, i could never understand the transition of pirmates to monkeys. If there is a forward progression, how come there is no backwards movements in nature? In other words what would take us humans to become monkeys again, vegetarian diet ,lol oops did I just say that?”

    And then what about rabbits turning into zebras? And then pigs having lambs? Where are all the “monkeys in the middle” so to speak?

  86. More on vegetarians having car accidents and other early deaths:

    This is a must see video:
    Pantox Laboratories
    4622 Santa FE St
    San Diego, CA 92109-1601

    Charles a. Thomas, Jr. PhD of Pantox Laboratories, San Diego, was interviewed on the video “Living to 100”, (which I have a copy of in my library), a subject of longevity that as one ages, and continues to drive an automobile well into old age, the most likely that person WILL have an accident, which could be fatal. A stunning example of this fact was the natural hygiene couple, who are called the “munchkins” of Florida (which are described as being somewhat short of stature,). Long term raw eaters Ruth and her husband who now live in St. Petersburg, Florida, were living in Miami, Florida. At the 1999, State O’Leona park gathering, Ruth told me about their car accident and it was the reason they sold their private home with avocadoes trees in the back yard to move to a retirement facility in St. Petersburg, Florida. According to her story, they were on the way back from their granddaughter’s wedding when their car was hit on the passage’s side, she suffered a broken hip and had to have surgery. She recovered, slowly, she told me, but dreaded having to go to the hospital. Ruth wrote a book about recovering one’s eyesight using the Bate’s method, which I have a copy of in storage. As far as I know, they are still alive. Although I no longer am in touch with the older NH folks.

    And, then there was long term vegetarian, 91 yr. old, never married and child free, Edith of my home state. She suffered a terrible accident midday going to the local bank. Her 1988 Olds was totaled. She survived with minor cuts. Still living alone, she now relies on the local mass transit and walks everywhere if she can. Three weeks after the accident, she fell in her year and hurt her sciatic nerve and broke her wrist. At that time, she was having a caretaker living in part time. Now in 2009, she is doing OK. I have not seen her in a while, though.

    In Spring 2006, prior to Vihara Youkta’s death, while I was visiting with her and Victor, she told me that long term raw vegan African-American Karyn Calabrese, owner of Karyn’s Fresh Corner in Chicago fell and broke her knee caps. Don’t ask me how she (Karyn) fell or where. I am only telling you what I was told while visiting Victor and Youkta in Simms, Arkansas at their farm. I am sure they would not lie to me. (smiles)

    In the book, The Live Food Factor” by Susan Schenck, she reported on an elderly man, who was long term raw eater who died as a result of a car accident injuries. Was he this author’s husband, How I Conquered Cancer Naturally by Edie Mae? I stand to be corrected on this one.

    I wanted to let you know, that long term vegan, 51 yr old, divorced and no children, well known Nina Domby, R.N. (retired) and massage therapist died of ovarian cancer, while I was at college in Texas, two years ago. I found out when I returned to my home state, seeking her for a massage. Everyone at the spa was shocked that I did not know she had died. I was at the University of Texas (south Texas tropics area) for a year, and did not keep in contact. Ms. Domby had a large massage practice and worked at the local spa on the weekends as well. She was a hard worker, it was sad to hear the news. I must add that she was overweight as a vegetarian and never exercised. I do know this for a fact. She owned a farm in the rural part of my state, and always attended the vegetarian potlucks.

  87. Phuq the Eejits who out-point type-o’s.
    Reading Engrish from 400 years ago one will get the point …namely that whilst we may feel in our limited hominoid time frame that lingo is a steady state thang i.s spelling grammar context etc.It is assuredly not so pointing out the spelling when one has gotten the meaning is just some nasty little primate dominance put-down..hence the first sentence.

  88. EMAIL 12/05
    Re: [INHS] Goldberg on Living Long

    >1) Having family ties
    >2) Active life (but not athletes)
    >3) Major dietary factor is “undereating” i.e. not engaging in luttony. This is the major dietary factor
    >4) Some type of spiritual beliefs/practices (no particular religion)

    >Being a “Hygienic Professional” is particularly stressful for a number of reasons including the poor understanding both the public (and so called >”Hygienists”) have of us. Very little support, legal hazards, unrealistic expectations from clients, etc. I hope to address some of these problems in a future
    INHS newletter article. >Paul A. Goldberg, M.P.H., D.C., D.A.C.B.N.

    With best wishes,
    Paul A. Goldberg, MPH, DC, DACBN
    Director, The Goldberg Clinic, Clinical Chronic Disease Epidemiologist , Diplomate of The American Clinical Board of Nutrition

  89. John wrote:

    “Isn’t it just a case of usefulness versus uselessness? If a mutation provides an advantage, it tends to stick. If that once-advantage ends, the mutation can atrophy. I’m pretty sure that there are species that “lost” their eyes, for instance, when they became dark-places dwellers. No doubt parts of our bodies have devolved over the ages, too.”

    As I understand it, a mutation does NOT have to be immediately useful to “stick.” Stephen Jay Gould has written about this frequently. Consider that fish that has a little wormy thing that grows out of his head that attracts other fish for him to feed on. Cool adaptation, huh? But this didn’t happen all at once. The end result definitely proves useful, but what did the vestige of this appendage do? How was that little nub immediately useful?

    Mutation is simply mutation and it is the process of evolution. I’ve always thought of it in exactly the opposite terms to what John wrote. Evolution results from mutations that are NOT DISadvantageous. Make sense? If a mutation (like being born without a limb) provides a distinct DISADVANTAGE, especially in the sense of survival and attracting mates to pass along the mutated gene, it will likely not be passed along, and evolution doesn’t “happen.” If it does no harm in terms of survival and reproductive ability, it MIGHT be passed along even though it is of no value at the “moment.”

    The long neck of the giraffe is indeed useful in eating leaves higher up in the trees, but what good is a just slightly longer neck, which an ancestor of the modern-day giraffe surely possessed?

    Gould also wrote about species that have indeed evolved to be capable of sight, then evolved to NOT be capable of sight, and back again.

  90. So, now I’m confused.

    @Tim: I’m curious about how we get nutrients from vegetables.

    @mreades: Cooking helps. It’s difficult to get a lot of nutrients without cooking. Some are available, but not as many as after cooking.

    Why are so many people telling us that we should get as many of our vegetables as possible RAW and WHOLE ? What’s up with that?

    They’re clueless. There is a movement to eat everything raw. People in the forefront of that movement believe that raw is better than cooked. But it often isn’t, especially with vegetables. It’s difficult to extract all the nutrients and calories from vegetables when they’re raw. If you are interested, a good book laying this all out (and mentioning “The Expensive-Tissue Hypothesis”) is Catching Fire: How Cooking Made Us Human. The book stresses how cooking as compared to eating food raw (een meat) makes more nutrients available. It pretty much lays waste to the eat-raw bunch.

  91. but what good is a just slightly longer neck, which an ancestor of the modern-day giraffe surely possessed?

    It would have been good to eat the foliage of the time.

    Trees respond to evolutionary pressure too.

    If it does no harm in terms of survival and reproductive ability, it MIGHT be passed along even though it is of no value at the “moment.”

    Or it might be passed on, but not expressed. Here’s a shot of a snake found in China last week. A birth defect caused a vestigial foot to be expressed, with which the snake could climb.

    a href=””>Snake with foot found in China

  92. OT: Banjo? Awesome. What style? I’ve been slowly trying to teach myself bluegrass style. Make that VERY slowly.

    A 5-string banjo, my own style, I guess. I just figured out the chording and kind of pick my own style. I haven’t even picked up a banjo for a few years because mine was stolen in a robbery at our house in Boulder. My guitar and (fabulous sound) 150-year-old violin got nabbed, too. I’ve replaced the Gibson guitar but not the violin.

  93. I think the book “The Vegetarian Myth” nails down all the reasons why vegetarianism is wholly unnatural and why agriculture is mostly responsible for the destruction of much of the biosphere.

  94. Not to belabor it, but I’ve thought of a bit more about my hypothesis that we can vary our metabolism through different levels of mental exertion just as we can for different levels of physical activity (perhaps even more). We all know from brain scans that neural response is much greater in intense activity (like taking a test) than passive activity like watching television. I personally recall walking out of various law school exams feeling physically exhausted.

    But the question – how much exertion/how many calories burned? Probably a simple experiment to calculate the calorie burn of a human lab rat doing various mental tasks versus physical activity. We’ve all seen the tables (how many calories burned walking/running/swimming per hour) but the comparison is to physically resting. That’s because “everybody knows” that physical exercise uses calories but anything you do sitting down is unimportant in that respect. Your information about the brain being more high-powered than muscles seems to put that common wisdom in doubt.

    If the number is significant — big mental exertion burns big calories — I can think of two immediate implications. First, under the Taubes principle, people doing mental work are going to get hungry, and should budget calories accordingly. In addition, this further amends the advice to weight-loss wannabies to toil away at the gym. Perhaps the library or video arcade would be just as good or better.

    Really fun musing (with knowledge that I’m probably wrong) — thanks to another great Dr Eades post.

  95. Also an artist Mike? Maybe my boss is right… she keeps telling me that it is not uncommon that people in science usually have a strong artistic side as well… Who knows… I play piano and organ (or anything with a keyboard for that matter), paint (though that hasn’t happened in eons), use to sing in an a Capella quartet and enjoy relaxing doing graphic design… My ex-wife used to say that because of the musical ear, I was able to learn languages without too much difficulty as well. Or maybe our brains just want to compensate with something ‘softer’ to contrast the science side and keep us sane! I would have loved to learn how to play guitar!

    It’s never to late to take it up.

  96. Perhaps one can learn good writing skills; and one can learn to play an instrument, and become quite good with practice; but with regards to art — you either got it or you don’t. You can’t be taught the ability to capture a likeness. It you go into school without an ounce of talent, you still won’t have any when you come out.

  97. so, should intense mental activity be considered a valid and effective weight (fat) loss method?

    That would be nice, but I don’t think it would be very effective.

  98. With respect to WAPF vs. Paleo, the focus of WAPF is traditional foods, including traditional foods of the neolithic era, with an emphasis on dairy being raw and grains and beans being fermented. As it happens, I am lactose tolerant and have no acute sensitivities to any foods. But, in eliminating (for the most part) grains, beans, and dairy from my diet, I have been able to see how they are still suboptimal foods, despite humans eating them for 10,000 years and me being relatively well adapted to eating them. I am, of course, in complete agreement with WAPF’s position on dietary fats, but with its heavy emphasis on neolithic foods, I think WAPF is primarily valuable for people beginning to shift away from SAD diets. I think if people are interested in truly optimal nutrition, they’d do well to ditch WAPF and shift to a more paleo diet.

  99. Dr Eades,

    Great post, but I think there are some missing ingredients. Alot of people are asking why didnt other carnivores evolve big brains like us and im not really buying into the “selective pressures” thing. I think the special ingredient is cooking. We are afterall the only animal on the planet that is both a meat eater and a cooker.

    I know you say “But the brain took a growth spurt before the advent of cooking,” but I really have my doubts here. Raw meat for the most part is extremely unpalatable, requires considerably more chewing than cooked meat, and pathogen contamination risk is much higher. Further, raw meat is significantly less satisfying after consumption. Just try eating a piece of raw bacon, its a fascinating self experiment.

    You will find yourself chewing it for ages and then finally when you “feel” its ready to swallow your more than likely to just spit it out. Raw fish is indeed much more palatable than raw land animal flesh, so perhaps the art of fishing came before cooking which would help bridge the gap bewteen the meat eating brain spurt and cooking. Dairy is important point I think, I find all dairy extremely palatable and satisfying, digestion feels really good. A glass of milk goes down much better than a glass of fruit juice.

    It may not have clicked with some people about dairy aswell, but that alot of animals seem to instinctively prefer cheese. Everyone “knows” mice love cheese and eat it, but cheese is not a natural food. A mouse would never find cheese in the wild. I remember seeing an experiment done with a squirrel, putting different food sources in closed chambers where the squirrel would have to go around and taste each food sample and then finally choose one, the options were nuts, bread, sweets, jam, cheese and insects. Guess which one the squirrel finally chose? It was the cheese! Amazing, given again the squirrel would never find cheese in the wild.

    So to sum it up, I agree that meat eating was indeed a huge step in the development of big brains and that humans are no doubt meat eaters by nature, but if you look at the anecdotal evidence, there is certainly ‘something’ missing. Why havent other carnivores got big brains? The answer for me has got to be cooking.

    P.S. Once again great post, its clear you worked very hard on it, surely this is one of top blogs on the net 🙂

  100. Forgot to mention I really enjoyed the little discussion on the metabolic costs of organs VS muscle mass. It too has been my experience that muscle mass doesnt boost ones metabolism as much as it is claimed.

    After I started commuting to work by cycling, I noticed a significant jump in my apetite, however despite putting on a thick layer of muscle on my legs and buttocks, I still need to avoid the carbs to avoid weight gain. Gary Taubes was right on the money when he said exercise doesnt help weight loss it only makes you hungry.

  101. I don’t think anyone has answered this concerning cats: “If that is the case then either Kleiber’s law is violated and they have a lower metabolic rate OR there is some other metabolically expensive tissue that makes up for it (instead of brain matter).”

    Musculature: They move much faster than us, can jump higher, etc. Their evolutionary solution to the game of life was physical, ours was mental.

    Heart Rate: Average human 72 bpm. Average cat heart rate is 160 bpm (120-200).

    Most cats do spend more than half the day sleeping.

  102. After a Sydney-wide ineluctable ostent — for Lo! the sky turned blood red and all took on a Martian hue — the Six Sennight Remedial Treatment for Elimination of Superfluity of the Central Circumferences for the Young At Heart (Though Not in Years) has arrived through the good offices of the local dak wallah. At last, God-like physical perfection will soon be mine (cue evil laughter: Mwaaaah Hah Hah!).

    Can’t wait to see a photo of the God-like physical perfection that shall ineluctably be yours. Get to work.

  103. What about eating salmon or fish oil instead?
    What about the prostaglandins in meat vs. fish?

    Salmon or fish oil instead of what?

    There are no prostaglandins to speak of in either meat or fish, only the raw materials, i.e., fatty acids, to make them. Wild game and grass fed beef has plenty of omega-3 fats.

  104. I was just about to recommend the Wrangham book! It’s a pretty cool book…it’s so sad how much more anthropologists and food historians (I’m studying it currently and they all mention the importance of fats and proteins for the population) just “get it”, and how our nutritionists are in the dark.

    I’m not sure if it’s been asked before in the comments (if it has, you don’t have to answer), but what do you think of the effects of low-carb on um…ethnic groups? I admit there’s some personal concern involved…I’ve tried over and over but low-carbing makes me carb-binge. My happy carb range is 100-140, any lower and I get the binge feeling, and any higher I feel ecky. I was wondering if being Chinese might have anything to do with it? Or maybe rice and fruit carbs (my main sources) are better than wheat carbs?

    I was just thinking, if northern Europeans can develop lactose tolerance, when fresh milk hasn’t been consumed that long (well, comparatively speaking), then maybe certain populations have a little higher tolerance for carbs.

    Thank you for your time!

    I’ve had patients from multiple ethnic groups following low-carb diets, and I’ve seen no major differences between how well people from the various ethnic groups do. I have nothing to base this on other than my own personal experience with a lot of patients, but I think there are more differences between individuals than there are differences between ethnic groups in general.

  105. Wow, that was a really clear explanation of research, not typical for the average blog.

    I do have a question. I have read this in other places and have found it very convincing. However, I read a book recently that adds a piece to the evolutionary puzzle, and I’m wondering how much this piece changes the meat vs. veggies equation. The article above clearly points out that in order for our brains to develop, our guts had to give, and in order for that to happen, we had to get more nutrients from our diet with less work on our digestive system. This means our diet had to change. The book I read is called Catching Fire: How Cooking Made Us Human. It’s a fun read (totally and hilariously demolishes raw foodists), and is very enlightening around the evidence for when cooking was introduced and the role that played in our evolution. He doesn’t make a vegetarian vs. carnivore argument in the book, he only talks about evidence for cooking, and how that improved the quality of our diet by allowing us to get more nutrients out of our diet, taxing our GI system less, allowing that to provide the give so our brains could take. Sound familiar?

    So I’m wondering this. How do you make the argument that it was cooking plus meat, rather than cooking alone, that gave us the nutritional ease of digestion we needed to develop our brains? As I said, he made his argument on the overlooked importance of cooking alone and doesn’t really touch this debate. I believe a case can be made that even with cooking you can’t get enough out of a vegetable-based diet to allow for this kind of evolution. But I don’t know if there’s evidence for this suspicion of mine. Have you read any research that specifically addresses this?

    Anyway, great post, great explanation. I found you through Ferriss and I’m glad I did.


    I’m glad you found me, too. Welcome aboard.

    Catching Fire is an interesting read, especially as he lays waste to the raw foodists. He references The Expensive-Tissue Hypothesis in the book as do the authors of The Expensive-Tissue Hypothesis mention cooking as a possibility. The first rapid expansion of brain size came prior to the advent of cooking, so it would have been difficult for cooking to have been responsible for that one. Maybe cooking was involved in the second expansion, maybe not, but we know it wasn’t involved in the first.

  106. @kris – Betty Edwards begs to differ with you. Capturing a likeness can be taught. See “Drawing on the Right Side of the Brain.” Can you imagine if we taught reading this way: “only 1 or two natural readers in a classroom – comes from a family of readers – has mysterious reading talent that regular people don’t -” – that is how we talk about drawing and Edwards proves it can be taught like reading can.

  107. Statins degrade the brain and heart.
    table sugar degrades the liver and clogs the arteries
    wheat degrades the digestive system, befuddles nutrient absorption, addicts the brain
    frankenstein fats alter (for the worse) all the membranes of 100 trillion cells and wreck havoc on steroid hormone manufacture and balance.

  108. Dr. Mike! Thanks for the great post!

    Do you know about the Red Queen theory of evolution? It’s quite a fascinating theory on the “why we developed big brains in the first place?” issue. According to it, it boils down to “sexual” selection, in essense we developed big brains because of competition with each other in contrast to other species, competing for power and hence more potential mates. It does explain also why non-vital skills (such as singing, art and the such) are highly valued in most societies, and they’re the most efficient at getting one mates.

    Our brain is the peacock’s tail, expensive but impressive.

    I’d recommend the book “The Red Queen” by Matt Ridley, it does a wonderful job of explaining this theory.

    All the best and thank you so much!

    1. vegetarians have higher levels of advanced glycation endproducts (sugar-fused proteins) than meat eaters. The people doing this research expected to find vegans had fewer AGEs because cooking meat produces them. But they are also formed in the body from carbs (reducing sugars) and homocysteine; the vegan diet is so low in B12 and B6 that homocysteine is also high.
      Omnivores may cook meat but it seems that vegans are cooking their own insides to account for more AGEs

      Plasma levels of advanced glycation end products in healthy, long-term vegetarians and subjects on a western mixed diet
      Katarína Šebeková, Marica Krajčovičová-Kudláčková, Reinhard Schinzel, Veronika Faist, Jana Klvanová and August Heidland

      Background Evidence indicates that food-derived Maillard’s reaction products are absorbed and yet can be detected in the circulation.
      Aim of the study
      We postulated that consumption of the heat-treated food by omnivores could be reflected by higher plasma levels of advanced glycation end products (AGEs) in comparison with vegetarians, who in cooking (by keeping away from meat) use lower temperatures and less time for heating.
      Plasma fluorescent AGEs (350/450 nm) and Ne-(carboxymethyl)lysine (CML, competitive ELISA) levels were investigated in 3 groups of healthy vegetarians (9 vegans-V, 19 lacto-ovo-vegetarians – VLO and 14 semi-vegetarians – VS) and compared with those of age-matched omnivores (O, n=19). Mean duration of vegetarian diet was V: 7.2±1.0, VLO: 8.2±0.8 and VS: 7.9±1.1 years.
      Both fluorescent AGE (O: 9.9±0.5; V: 10.8±0.7, LO: 13.1±0.8* and SV: 11.6±1.2 ×103 AU), and CML levels (O: 427.1±15.0, V: 514.8±24.6*, LO: 525.7±29.5**, SV: 492.6±18.0* ng/ml) were significantly lower in omnivores than in vegetarians. Plasma glucose, parameters of renal function (plasma concentration of creatinine and cystatin C, calculated glomerular filtration rate – GFR) as well as C-reactive protein levels were within the normal range and did not differ significantly between the groups. Thus, neither decline of kidney function nor inflammatory processes contributed to the rise in plasma AGEs.
      Enhanced plasma AGE levels in vegetarians in comparison to omnivores are herein presented for the first time. Mechanisms of AGE elevation and potential pathophysiological relevance of this finding are to be elucidated in prospective studies.

  109. @dreads If you are interested, a good book laying this all out (and mentioning “The Expensive-Tissue Hypothesis”) is Catching Fire: How Cooking Made Us Human. The book stresses how cooking as compared to eating food raw (even meat) makes more nutrients available. It pretty much lays waste to the eat-raw bunch.

    Thanks for the reference!! I followed your link and ordered this book from Amazon. I just got The Vegetarian Myth, too, but haven’t found time to read it yet. I’m going to the UK in two weeks, and I think I’ll have some time on a couple of long flights to get started reading these. Again, GREAT POST!

  110. Fascinating post as always! And it does tie in quite nicely with the theories in “Catching Fire: How Cooking Made Us Human” which I just read last week (and which I see you have read). Of course Wrangham’s theory is that it was cooking (which made food more easily digested and bioavailable) that led to our larger brains and smaller guts. But he certainly did seem to feel that it was the cooking of *meat* that a large part of that cooking was directed towards. I felt he made a good anti-raw case – and of course I agree with the meat-eating evidence. 🙂

  111. There are a lot of non-meat foods out there. Lately fructose has taken a big hit, including from you. Grains and especially wheat seem terrible for most of us. But what about root vegetables? Some primitive societies seem to have thrived on them. In my case, I never get acid reflux from potatoes, but do from sugars and grains. Rice seems less problematical than wheat. Is it possible that vegetables should be broken down into more categories?


    Dr Mike, this is the oldest living man and he shared his longevity secretes, its a small article. I know it is observational case and correlation is not causation but if you had to venture an educated guess what would you say contributed to this man’s long life:

    A. Great genes and it doesnt matter what else he does
    B. Eating two meals a day and skipping supper
    C. Eating wholesome food and lots of fruits
    D. Being physically active and working hard
    E. Taking baby aspirin
    F. All of the above
    G. Have no clue, thats a question thats impossible to answer

  113. Thanks for some very thought provoking articles. I think I’m going to have to embed the ETH paper into my blog.


  114. Wow, after reading the comments on Mr. Ferriss’s blog, I have come to the conclusion that you have a heck of a lot of patience. More than I ever would.

    I have the book, 11 pounds in 11 days. I need a new belt.

    Lastly, as long as everyone else is adding to your reading list, I reccomend “The Black Swan” by Nassim Nicholas Taleb. It’s a philosophy book about logic, false logic and the impact of randomness. After reading your critiques of certain studies, I think it might interest you greatly.

  115. Hi Dr Eades,

    Great article. When you wrote in PPLP of the very convincing theory that is ETH you really meant it.

    However, I’ve got to say I disagree with Aiello and Wheeler’s theory about meat eating as the explanation for the first big jump in brain size two million years ago. I believe it was the progression into upright walking that the record shows was possible at that milestone, with the increased Lumbar region of the spine, 20% in chimps and almost double that at 40% in modern humans and more flexibility from not needing a rigid lower back for knuckle-walking– also interesting that Chimp Babies are half the size of Human Babies. The bigger pelvic region allowed bigger heads to develop. This also explains the fact that Brain size of the Australopithecines is the same as modern day Apes, and only increased slightly from 4 mya to the big jump at 2 mya. So I don’t think meat eating caused the first jump, but with the extra brain tissue we could then start cooking, which then must have allowed us to start shrinking our GI Tract.

    That’s the theory I believe anyway.


  116. I asked Gary Taubes why vegetarians tend to be skinnier (I asked you, too) and he said he thinks it is because they tend to eat food that is less processed.

  117. I read somewhere that while it’s true that replacing one pound of fat for one pound of muscle will only increase BMR by 3-4kcal/d, there is however another effect happening. Up-regulating untrained muscle to trained muscle will increase the BMR from 5.7kcal/lbs/day to 7.2kcal/lbs/day.
    Even someone with a very modest 50lbs of muscle would add 75kcal/d to their burn just by moving from untrained to trained status.
    Is that true?

  118. “Gary Taubes was right on the money when he said exercise doesnt help weight loss it only makes you hungry.”

    Oh, pity the poor overweight persons on The Biggest Loser who are consuming 1200-1500 calories per day and are exercising their 200-400+ lb. bodies for 4-5 HOURS per day! They work out until they vomit. And the diet/chef expert they just featured is, of course, anti-fat, going on about the high-fat chicken caesar salads that are baaaaad. Sad. (so why am I watching it? I’m showing my grandson what NOT to do).

  119. I’m a vegetarian who completely agrees that we evolved to eat meat.

    But I’m also a consumer in today’s society, and when I buy and eat meat, I am supporting a horribly broken system that is polluting our planet and our health. Wile and/or pasture-raised meat is unquestionably healthy, but factory-farmed meat, I’m not so sure about. It’s definitely not environmentally healthy, and it’s definitely not humane. I stopped eating meat because I wanted to “vote” for change to the way animals are raised and the way meat is produced.

    It’s easy to say “those vegetarians are idiots” if you assume that all of us truly believe humans are herbivores. But some of us are as smart or even smarter than you, and have given this a lot more thought, and can manage to lead healthy lives without meat. But you shut down any productive dialogue and fail to reach any new understanding when you take that approach.

    And yes, I agree, I could only buy pasture-raised meat and/or hunt for meat myself. Perhaps I will do that at some point. But my health hasn’t suffered for lack of meat. I am able to stay away from processed grains, trans fats and PUFAs, I get a good amount of mono- and saturated fats and protein. I, along with many other vegetarians, an do what we think is right to help change the system while remaining very healthy. In fact, I would hazard a guess that vegetarians who eat the way I do are much healthier than meat-eaters who rely on CAFO-raised animals.

  120. I’m coming from a raw-food, natural hygiene background, and I stumbled on your statement that cooked meat is easier to digest than raw meat. I’ve learned from NH that cooking meats deranges (deaminates) the amino acids, making them difficult to digest and causing much waste. Would you please point me to some references that show cooked meat is easily digested and doesn’t “putrefy” in the intestines?

  121. Hi Message for Michael Richards in Australia: I ordered “The Cure” through Dymocks and had it in less than 10 days.

    We’re on day 4, looking thinner, feeling great and the AM blood sugar has just come down (it was up around the high 6’s & low 7’s but this morning at 5.5. Lets hope it stays that way!


  122. You should see if you can wrangle an appearance on Dr. Oz. His wife the TV producer and vegetarian taught him all he knows about nutrition (People Mag last week). He desperately needs to be informed.

    Question on a carb quiz on show that aired 9/28/09.

    Which of the following results from a low carb, high protein diet?

    A. kidney failure
    B. kidney stones
    C. high cholesterol
    D. All of the above

    Answer: All of the above.

    Jesus wept.

  123. Dr. Eades:

    What have you or others written relevant to exposing and correcting such stupidity as is found in the article “Protein Overload”? See:

    I’d like to pass an analysis on to friends. I know someone who is following this guy’s diet (or who at least takes this guy seriously) for health reasons. Based on how jacked up “Protein Overload” is, I don’t see how following McDoug’s diet or advice can be in any way a good thing. He advocates vegetarianism, as I’d imagine you already know. See:

    I see you have some posts on vegetarianism that are relevant; I’ve already passed those on.

    Now maybe there is some strange, unusual reason for a particular person to have to be vegetarian — that, of course, is for a doctor to decide, not me — but we still need to do our research on diet and nutrition, and not get in horse blinders.



  124. Dr Eades, thank you for this article. This is a fascinating subject.

    Some comments on other commentor’s comments:

    It doesn’t make sense to make assumptions about the diets of ancient human hunter-gatherers by comparing them to modern peoples – the most fertile areas of the planet are now used for agriculture, and the remaining hunter-gatherers mostly live in marginal areas. Studying the diets of modern humans on the African savannah, Australian aborigines or Indians in the Amazon is not necessarily going to tell you much about homo erectus hunting mastodons. They were different creatures living in a different world.

    It’s not reverse evolution, but there were branches of our family tree that went in other directions. The robust australopithecines were true vegetarians – they had massive jaws and ridiculously huge molars for crushing seeds and grinding coarse plant material. They had small brains and no doubt huge guts to process this diet. They had a bony crest like a fin along the tops of their skulls as an attachment for powerful jaw muscles:

    Australopithecus boisei skull

    Evolution did not go in a perfectly straight line with us as the goal. The path meandered and went off on dead-end tangents. I’ve always found it fascinating that, until very recently, there were different species of hominid living at the same time.

    Many comments make the assumption that we developed big brains to be better hunters. The article and replies to the comments repeatedly say this is not the case – we don’t necessarily know what the pressure was to grow bigger brains, or what was cause and what was effect. Being smarter would make us better hunters, but that doesn’t mean that this was the reason. The point is not why we grew bigger brains, but how we managed to do it.

    Thank you again for writing this.

  125. To amplify a point already made a couple of times, cats and dogs (carnivores) are our most popular pets: they may not have the increased brain size but they have a far wider range of behaviours than vegetarian pets like guinea pigs. And who would keep a pet sheep or cow?

    To Pauline, Stephan has an excellent take on the “fat causes insulin resistance” paper

  126. The Biggest Loser is a good example of everything that is wrong with typical personal trainers. Most of them don’t know their heads from their asses, much less have any understanding of proper exercise or nutrition for fat loss.

    The most important role of exercise in a fat-loss program is not calorie-burning, but rather the maintenance of lean body mass while fat is lost, which will help preserve metabolic rate. The safest, most time-efficient, most effective method of accomplishing this is high intensity strength training performed in a slow and deliberate manner.

    I would love to see you guys and Fred Hahn get a fat-loss reality show that challenges the kind of nonsense shows like The Biggest Loser and Dance Your Ass Off are promoting as effective weight loss.

  127. This announcement has interesting implications for the theory that man evolved because of meat:

    Seems now that humans and apes evolved separately from this common, apparently rather omnivorous ancestor (“She is believed to have been omnivorous, eating berries, fruits and roots as well as small mammals.”) This species also walked upright much of the time and ate meat. So both humans and apes evolved from an omnivore like this 4.4 million years ago. Appears that those species that went vegetarian ended up quite a bit less evolved than those that stayed omnivores.

  128. The vegetarian myth about meat “putrefying” in the GI tract is interesting. Well, silly, but interesting on a personal level. I’ve eaten bad (i.e. old, brown) meat before – not on purpose – which I had no problems digesting; it just tasted and looked bad. In fact, the only times I’ve ever had digestive problems related to meat were the two times I ate tainted meat (food poisoning) and other incidents where the meat was accompanied by other foods (starches, mainly). Since adopting a *mostly* meat/eggs/dairy diet, I’ve had no constipation, and neither diarrhea nor a compulsion to vomit. In my experience, if the body wants a food out, it will find a way to get it out.

    Yet another reason to never trust the reasoning of activist vegan types. The more passive ones, I think, are mostly just misled – The Vegetarian Myth really opened my eyes on this subject, so thanks for that recommendation, and keep up the good work.

  129. The protein requirement of mammals is reflected in the protein content of their respective milks. Vegetarian mammals tend to need less protein and have lower concentrations of protein in their milk than do carnivorous mammals. For instance, cow’s milk is about 3.5% protein and goat’s milk is 2.9%, whereas cat milk is about 9% protein, and dog’s milk is a whopping 11%. Even omniverous rats have about 10% protein in their milk. How much do humans have in breast milk? An average of 1.1%. Some analyses have shown as low as .9% protein, and yet human infants can double their weight on it in six months. This is far more relevant than a grandose hypothesis about human evolution.

    Even if your figures were correct, your statement that “the protein requirement of mammals is reflected in the protein content of their respective milks” is false. But, due to the fact that you’ve obviously been listening to way too much vegetarian propaganda, your figures aren’t even close. The amount of protein in human breast milk is about 6 percent, not an average of 1.1 percent. I don’t know what the protein content of cows milk is, but it is greater than that of human milk, which means that it must be more than 6 percent, not the 3.5 percent that you list. Cows have practically no requirement for dietary protein, so how does that square with your theory? Sadly, your grandiose hypothesis is the one that is flawed.

  130. No! You’ve got it wrong. 6 or 7 percent is the amount of protein in milk based on percentage of calories! I’m talking about per volume of weight. In other words, in a 100 grams of human breast milk, there is about 1 gram of protein. And in 100 grams of cow’s milk there is about 3.5 grams of protein. Look it up. You’re way off! And to say that cow’s have practically no requirement for dietary protein? For goodness sake, a calf grows from 60 pounds at birth to 600 pounds in a matter of months. What do you think that weight is composed of? All fat? There’s bone and muscle and tendon and ligament and everything else that requires protein. I don’t know who you are who submitted that answer, but you are embarassing yourself.

    No, you’ve got it wrong. No one uses a figure for the amount of protein as a function of the total weight – most of which is water – of a liquid product or a solid product such as meat, for that matter. The figures used are either the calories from protein (or other macronutrient in question) as compared to the total calories in the substance under question or the absolute amount of a macronutrient without taking calories into account. Most scientific papers are written using the first method; those of us counting carbs use the second.

    I’ve never seen so many errors compacted into one small paragraph in my life.

    Where do you think the cow that grows from 60 pounds to 600 pounds in a matter of months gets the protein once it is weaned? Where does this protein come from if the cow is grassfed? Grass contains virtually no protein, so how does the cow build its muscle and tendon and ligaments and skin and hair? I’m going to let you figure that one out because I’m not responsible for either your ignorance nor your education. But you should think on it to see if you can come up with a reasonable explanation. And while your pondering the answer to that easy question, perhaps you should also ponder the quote below from Mark Twain. It sums up you situation to a tee.

    “It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so.”

    It is your gross ignorance that is on display, not mine. And I’m through with the debate. I’ll be happy to provide you all the space you want to display it further, but don’t count on me to reply.

  131. Great article, thanks! Couldn’t agree more. I found a reference to the composition of raw grass fed cows milk.
    From the article “Whole raw milk’s composition varies slightly among cow species, type of food and other conditions, so the figures below are only approximations.” The figures where provided by a commercial raw milk dairy: Fat 9g. Protein 9g. For what it’s worth.

    I would think it is the fat content in human milk that tells the real story. I found this at Weston Price website

    Fat and Cholestral in Human Milk

    Glad I found your blog. 🙂

  132. Human milk contains protein some 11…20 g/L. The protein content varies, the highest content can be found in colostrum. Cow’s milk contain protein 32 g/kg (or more, colostrum 46 g/kg). The dog’s milk contains protein 75,3 g/kg according to this study:

    I’d say the protein content reflect the age of weaning, not the diet. Puppies are weaned at the age of 4 weeks, human kids at the tender age of 4 years.

  133. What long term study has ever shown consumption of meat in large quantities has successfully reversed advance heart disease (the No. 1 killer in the west)?

    A few links to articles produced by practitioners that have reversed heart disease.

    If the billion dollar meat industries could prove that consuming meat in large amounts can reverse heart disease they would have provided these results. All studies that have done such have always been plant based.

    Another interesting piece from Joel Fuhrman’s blog.

    Although there is not a lot of strong evidence to show that very small amounts of animal products in a diet will result in an adverse effect (although the China Study has evidence that it may cause harm), the best diet for humans needs to nutrient dense, whole food and plant based (not necessarily high starch) to ensure we have a low risk of developing the diseases that most westerners succumb to.

    There are a couple similarities between humans and omnivores, however there seems to be far more evidence showing that out digestive system, jaw and teeth etc. are more similar to that of a herbivore than an omnivore.

    People who make comments about consuming carbohydrates (when from nutrient dense whole foods) in large quantities as causes of obesity, heart diseases, type II diabetes are simply ignoring billions of people in the world from parts Asia, Africa and South America where all these problems are near non-existent (especially in the past when Western diets were not widely consumed).
    The following article relates to how the high protein diets/low carb diets really work and explains the consequences of these dangerous diets.

    We should not to be focusing on what humans consumed in the past, and we need to concentrate on what we should be consuming now to in order prevent disease and premature death as well as sustaining the worlds population. If meat does have benefits, we should be concentrating on what portion it should make up of our diet rather than advising unlimited amounts of meat.

  134. Do you have any strong evidence that nutrient dense vegetarians diets with adequate calories shrink the brain?
    Do you have any strong evidence that nutrient dense vegetarians diets with adequate calories make people stupid? If you do your research you may find that the opposite is true.
    Do you have any strong evidence that nutrient dense vegetarians diets with adequate calories have ever caused a protein deficiency leading to disease? Well there are tens of thousands of people who have developed kidney stones due to the over consumption of protein.
    A vegan consuming frequent B12 supplements have a lower chance to develop a B12 deficiency when compared to the typical meat eater.

  135. Ralph Cinque is referring to the percentage of protein per weight.
    Even wikipedia’s article on milk lists the percentage of protein per weight:

    According to 3.7% fat milk (standard milk) is 22% protein when going by % of calories and not weight.

    For any animal, cow or human, the muscle, hair tissue etc is made from protein. Cows have a large body mass and like any other animal their tissue frequently breaks down and needs to be replaced with protein. “Calves…. double their weight in 47 days (as opposed to 180 for humans), grow four healthy stomachs, and weigh 300 pounds within a year”.

    Why would we need to consume more than 6% protein after being weaned if this is the percentage required for the human baby which is the period (I need to confirm this) where we grow the most rapidly.
    “According to the World Health Organization (WHO), the average 150-pound male requires only 22.5 grams of protein daily based on a 2,000 calorie a day diet, which means about 4.5 percent of calories should come from protein. (WHO recommends pregnant women get 6 percent of calories from protein.) Other nutritional organizations recommend as little as 2.5 percent of daily calories come from protein while the U.S. Food and Nutrition Board’s recommended daily allowance is 6 percent after a built-in safety margin; most Americans, however, are taking in 20 percent or more.”
    Taken from

    And I ask you, where does the protein to fuel this growth come from. Hint: It ain’t from the grass that they eat. Get with your buddy Ralph and see if you two can figure it out.

  136. I am curious as to why is it so important for you to be “right” about us being carnivores, which we clearly, empirically are not. We are omnivores. We eat just about anything we come across–your wife’s blog entry extolling the virtues of chocolate covered bacon, and mourning the loss of her ability to consume cheetos and chocolate chip cookies simultaneously, proves that fact more perfectly than any peer reviewed article ever could. Offer that bacon candy bar to your cat and your dog–the carnivore cat will walk away disinterested and the omnivore dog will wolf it down (dogs are omnivores too, as are their relatives wolves, foxes, coyotes, and bears–some prefer meat more than others, but all will eat whatever they can find, if they can’t find meat).

    You seem to have had some unpleasant encounters with vegetarians, but even so I cannot understand why it is necessary for you to wage an ideological war with them, nor how that advances your books and the good you do by alerting Americans to the fact that the food they have been indoctrinated to eat for the past 30 years is making them fat and ill (it is also making them passive and apathetic, and I think that fact goes along way to explaining why our government pursued its dietary propaganda program when it did in the first place).

    I am not a vegetarian. I have never been a vegetarian. I have no plans on becoming a vegetarian. But I have known many vegetarians in my life, none of whom chose vegetarianism for nutritional reasons–all of them chose it for moral reasons: Many where Hindu and the rest were people who ran the gamut from just opposing the way industrial agriculture treats the animals (which I oppose as well) to those who felt that it was wrong to eat something they could not bring themselves to kill and butcher themselves (and if I was forced to kill and butcher my own food, I would be reduced to fish, eggs, and dairy). None of the vegetarians I have known ever made any attempt to proselytize their dietary choice–most were almost apologetic about it whenever it came up. In fact, it was far more likely that they were the ones who would be ridiculed, or at least questioned about it as if they were from Mars.

    I’m well acquainted with the Expensive-Tissue hypothesis; every anthropology student learns about the hypothesis in Bio Anth 101. But you are misusing it–it does not and cannot say what we ate. It only provides a possible explanation for how our brains were able to increase in size. One crucial factor you do not mention (and your pithy dismissal of the question about lions not getting big brains because they didn’t need them, hints that you may not be aware of it), is the fact that all primates allocate a larger percentage of our total energy to our brains than do any other vertebrates (humans 20%, non-human primates 13%, all other vertebrates 2-8%). So even the dim-est bush baby is allocating almost twice as much of its energy to its brain than is the smartest non-primate vertebrate. Perhaps because we are a visual family of animals?

    Homo Erectus (2 million-200,000 years ago), the first large brained hominid, was predisposed as a primate to allocate a significant amount of its energy to its brain–its teeth shrank along with its gut. Lions aren’t. It would take pretty big leap for evolution to be able introduce that into the lion gene pool, but not so much for Erectus–the potential was already there.

    Teeth shrinkage has accompanied brain enlargement all the way to modern humans (while our brains have not gotten much larger for the past 200,000 years, our teeth have continued to shrink to this day–but not our guts, which strongly indicates that it was cooking and food preparation (which has continued apace for the past 2 million years), not meat consumption that was responsible for all three–classic chicken and the egg: Was it cooking that made a large gut and big teeth unnecessary allowing for a bigger brain, or was it meat consumption alone?

    I say cooking, especially since we can’t really eat raw meat: (1) Home Erectus’s brain starts off about the same size as an Australopithecine’s (750 cc’s) and ends only up about 150 cc’s shy of ours (1350 cc’s, and the same size as ours when we very first appeared); (2) our guts and brains seemed to have reached their respective minimum/maximum trade off long ago, but our teeth (and our physique generally) have continued their gracilization trend, regardless of the percentage of meat in our diet; and (3) our food preparation and reliance on tools have continued to intensify. Cooking increases the bio-availability of almost all foods for us. This theory is pretty big right now–that it was cooking that made us human, meat was just an afterthought. I don’t know the answer. No one does.

    But now for the monkey wrench, while cooking and/or meat allowed for smaller teeth, smaller guts, and larger brains none of that would have just occurred because it could, unless Homo Erectus, and later Homo Sapiens, found the results sexually appealing–and this is where my own research comes in. We have been getting more and more delicate for the past 2 million years, and cross-culturally, ideals in beauty for both sexes favor delicate features over coarse features–for the first 800,000 years those Erecti who were more delicate looking, thus more beautiful, were also those who were using the tools the most and had the biggest brains–the answer in evolution always boils down to sex.

    My area of interest, the Mesolithic Transition, has had me trying to figure out why an intelligent, sensitive species that is hard-wired for egalitarian social relationships, would adopt agriculture and accept the ensuing inequalities and hierarchies it brought with it, not to mention the back breaking labor (albeit that the rate of transition was only 1 mile every 100 years)–were they forced by circumstances? Maybe…but a forager’s response to climate change is simply to move. The upper paleolithic people were more robust (i.e. less beautiful) than the Mesolithic people and the Mesolithic peoples were more robust (i.e. less beautiful) than the first Agrarians (and while we have in some cultures regained our height, we a re still slighter than they were)…that’s what got me to thinking that maybe it was beauty/sex, but then of course you have to account for the bad breath and rotten teeth that resulted from eating sticky grains and starches…so i’m not quite there yet…

    All that being said, plenty of brilliant, old Hindu’s show that meat consumption is unnecessary for cognition or longevity–so I am back to where I began: Other than scoring points against the “other” team, how does this war against vegetarians/carnivore mantra advance your central cause of helping 21st century Americans fight diabetes, obesity, heart disease etc? I just don’t get it…

    PS: I actually think that fat consumption will prove more necessary for brain health and cognition than protein consumption in the future (so many brain problems seem to be treatable simply by increasing fat intake…)

  137. What is the fat content respectively of human, feline and bovine? This would be important in conjunction with the protein. Especially since the infant human brain develops on high fat and needs relatively great amounts up to age two.

  138. The human being ate meat, got big brains and created a world with large scale hierarchic wars, pollution, viagra, antidepressives, reality TV etc. Yay for the human brain! Copernicus realised that all the planets don’t circulate around the earth, but somehow the notion that the human being is the centre (and top) of everything still lives on.

    Actually, i can’t really see any correlation between a persons diatery choices (or non-choices) and intelligence (a word that doesn’t really say much anyway).

    I know both vegans and meat eaters who are exceptionally smart, mature, compassionate and healthy.

    There are (of course) more variables to it.

  139. I always find it ironic that the capacity in humans to feel remorse for eating animals would not exist at all if we hadn’t begun to consume animals.

  140. I figured it out and learned something new. I knew that cattle have microorganisms that break down cellulose into simple sugars, but I didn’t know that cattle get most of their protein from microbial protein synthesis. The human stomach and small intestine secrete proteolytic enzymes, so the human diet obviously requires foods that actually contain protein. Since cattle can synthesize protein from the non-protein components of their diet and humans can not, it doesn’t make sense to compare humans and cattle in terms of required protein intake. What I’m not sure about is where the microbes get the nitrogen to make the protein, but I would guess that it’s the nitrates that are naturally present in grass; rumen is a liquid, so I wouldn’t think that there’d be enough air in it for nitrogen fixing bacteria.

    I see you decided to do Ralph’s homework for him. You’re almost there. Read this paper to get a little further along. I’ve got to do a long post on this subject sometime.

  141. I always find it ironic that the capacity in humans to feel remorse for eating animals would not exist at all if we hadn’t begun to consume animals.

    This is the most brilliant observation about vegetarianism, ever.

  142. To Alex – The microbes in the rumen get nitrogen from the nitrogenous materials contained in the plant material they consume. Simply put, legumes (clovers, alfalfa, etc) “fix” nitrogen via micro-organisms that live in nodules on their roots. This nitrogen is used by the plant. When that plant tissue is eaten the animal’s microbes can utilize it. Urine and dung from the animal, as well as decaying plant tissue, release nitrogen back to the soil where grasses, and other plants which can’t fix nitrogen, can use it for their growth.

    Tom – Agreed!!


  143. This is Ralph Cinque, and for those interested, I continued the debate with Dr. Eades on my own website, and I’ll give you the link:

    There’s no need to debate whether it’s proper to look at protein as a percentage of calories or protein as a percentage of weight in milk. The point is that EITHER WAY YOU LOOK AT, HUMAN MILK IS THE LOWEST PROTEIN MILK IN THE WORLD!

    And the notion that cows only survive as vegetarians because of all the bacteria they grow is nonsense. The world is full of vegetarian animals and of many different kinds, both ruminant and non-ruminant. It’s nonsense that only ruminant animals have the capacity to be vegetarians. Besides, unlike cows, we humans do not live on grass. We’re definitely not like them. We can eat fruits and nuts. And we have many vegetables that are much less coarse and fibrous, and far more digestible, than grass. We can also eat whole grains and legumes. Hey, the above is what I eat. And I’ll bet serious money that I can lift a greater percentage of my body weight than Dr. Eades can. I’m almost 59, and I presume we’re close in age. C’mon, Doc. I’m chalking up my hands.

    Beware. A note of warning. If you spend any time on the above website you risk serious brain damage. After reading a little of it myself, I now understand where Ralph is coming from.

  144. I just checked out the link that you gave to Alex re ruminant digestion. Wow!
    How do you find the time to find this stuff.?
    Love this blog. Keep up the good work.

  145. Certainly, this is all fine. I have no reason to dispute the research. However, I do find the conclusion very myopic for the following reasons:
    1. Meat may have been the most efficient source of nutrition in that phase of our evolution but the same effect could have been achieved with the right combination of plant-based foods. We simply did not possess our current level of knowledge then.
    2. If we had also consumed more of the plant-based superfoods we know about now, probably our evolution would have been even more efficient.
    3. Why should we justify eating an animal-based diet now simply because it worked in the past. With our expanded nutritional knowledge, we can now achieve the benefits of a meat-based diet plus more.
    4. The food we eat is no longer simply the food we eat. In this stage of our evolution, it has significant political and ethical, etc connections. We can maintain excellent health on a plant-based diet and also satisfy ethical considerations. Perhaps this is in fact the next stage of our evolution.

    I would urge you to move beyond retro-focused justification of meat-based diets and consider what nutrition would be most effective for our continued evolution, both physically and spiritually.

  146. I’ve only skimmed the comments so I hope I’m not repeating something that has already been said.

    It’s been a while since I was an undergraduate anthropology major (finished BA in 1999), so no doubt the exact theory has moved on somewhat. However, one important more-or-less accepted idea regarding food sources for early hominids (e.g. Australopithecines) was that their ability to make and use tools allowed them to scavenge more food, especially bone marrow, from the leftovers of other animals’ kills. This was because they had the mental ability and the manual dexterity to make and use tools that would allow them to effectively crack open large bones which would have been difficult for, say, a hyena to get at. There is also the possibility that they were able to scare away other scavenging animals, but I’m not so sure about that.

  147. Below is table comparing human to other mammalian milks (based on weight, but the results would not be different if you looked at calories). Notice that human milk is not only the lowest in protein (by far), it is also the highest in carbohydrate- by far. 7% sugar in human milk is comparable to watermelon. So, human milk is the sweetest of all milks. And a human infant can live on (sweet) breast milk alone for two years. Imagine, meal after meal, being conditioned to a sweet taste. So, it’s not surprising that babies naturally gravitate towards bananas, cantaloupes, etc. because its a continuation of the sweet taste they’re used to. Humans also have the most dense concentration of sugar-detecting tastebuds on the tips of our tongues. Cats, (to which Dr. Eades compares us to) have no ability to detect sugar- at all. Check out the link. You can speculate all you want about the remote past, but this isn’t speculation: it’s reality.


    • Human: 3.8% fat; 1% protein; 7% lactose

    • Cow: 3.7% fat; 3.4% protein; 4.8% lactose

    • Rat: 10.3% fat; 8.4% protein; 2.6% lactose

    • Dog: 12.9% fat; 7.9% protein; 3.1% lactose

    • Rabbit: 18.3% fat; 13.9% protein; 2.6% lactose

  148. Ralph,

    This is very interesting. I wonder if the diet of the mother effects the macronutrient concentration? So could a woman eating a very low carb, zero sugar diet possibly produce less lactose by volume than a woman who eats the Standard American Diet?

    Also, if you look at protein not as energy but as the building blocks, I think the fact that these other animals reach adult hood so much more quickly than we do could explain why they all have a higher percentage of protein in their milk. If the cow, for example, physically matures 3 times as quickly as a person, that would account for the fact that they were eating 3 times as much protein.

    Just a thought. I am interested to hear what Dr. Eades has to say!

    And to Kym, read Vegetarian Myth, by Lierre Keith. Please, please read it. It’s wonderful, and addresses each of your points exhaustively and poetically.

  149. For 20+ years, I ate a diet very much in tune with what Ralph suggests, foolishly believing all sorts of new age hippy nonsense, and completely ignoring my body telling me in no uncertain terms that it was not the right nutritional approach for me. Reality is that a high-carb, predominantly vegetarian diet spikes and crashes my blood sugar and makes me fat and lethargic. Reality is that a diet of meat, veggies, and a little fruit sates my appetite, doesn’t spike my blood sugar, and effortlessly keeps my body weight normal. One thing I learned in all of this experience is that it’s best to listen to the body and not just blindly follow some external set of beliefs.

  150. Ralph,

    Most vegetarian propaganda lists the components of human milk by weight to deliberately create a misleading picture. You are incorrect to say that listing them by calories gives similar results.

    Fat has 9 calories per gram, carbs and protein each have 4, so according to your numbers human milk has over 20% more calories from fat than from carbs. On top of that, much of the lactose is actually there to feed the beneficial bacteria in the baby’s gut, which turn it into lactic acid and keep an acidic pH in the digestive tract – this prevents the growth of harmful bacteria which the baby’s immune system is not ready to deal with.

    Figures for the nutritional content of human milk are averages, because it can vary widely according to the mother’s diet and also for the same woman over time. It also varies considerably even during a single feeding – it’s initially quite thin, but as the breast empties it becomes much thicker and contains much more fat. I believe that there are even different names for the early and late milk.

    The quantity of protein in its milk is related to how quickly a species grows. Humans are among the slowest-growing animals on the planet, so human milk has proportionately low levels of protein.

    It’s also misleading to compare human milk to some of those other animals, because we are such different creatures. Humans nurse frequently throughout the day, so human milk is much less concentrated than the milk of many other animals. Cows would be somewhat similar. The other animals you mention, dogs, rats and rabbits, have mothers who must leave their babies alone in the den/nest/warren for much of the day while they are out hunting or foraging, so their milk needs to be more nutritionally dense than human milk, because those babies have fewer meals and consume much smaller quantities per day, relatively speaking. Humans normally have only one baby who gets the mother’s undivided supply of milk. The other animals have litters of four, five or more siblings who must share the limited supply of their mother’s milk (which is why all of those animals have more nipples than we do) and at the same time grow very rapidly, as they must be capable of living on their own once they have been weened in a few weeks’ time.

    Humans might indeed have a sweet tooth, but in the wild, locally-native berries and fruit would be about the only way to indulge it, and these would only have been available for a few weeks in autumn in most parts of the world (and, as has been pointed out in this blog, we’d be competing with birds and other creatures for those same goodies). A sweet tooth would encourage us to eat them when available, but it would be impossible for sweets to be a regular component of the diet before the relatively-recent introduction of agriculture.

    Fruits did not always exist in their present, high-sugar forms, either – the fruits we have today are the result of thousands of years of selective breeding of plants that have been collected from all over the world, and bear little resemblance to their smaller and sourer ancestors.

  151. Let’s not get off-point here. And the point is that if a human infant can grow and develop and double its birth weight in 6 months on a diet of nothing but breast milk, which has either 1% protein by weight of 7% protein by calories (and both figures are low) then why should I, an adult human, who is not growing at all, who is just hovering, maintaining, require a high protein diet?

    And to answer Bryce, yes, the composition of a woman’s milk does fluctuate depending on her diet, but usually within a narrow range. It’s genetically determined. It’s not like she can double the amount of protein in her milk by doubling the amount of protein she eats.

    To Paul, you’re correct that breast milk delivers more calories as fat than as carbohydrate. Over 50% of the calories are from fat. Happy? But what you said about the lactose primarily feeding the bacteria, you will have to provide references for that. On Wikipedia it just says:

    “Infant mammals nurse on their mothers to drink milk, which is rich in the carbohydrate lactose. The intestinal villi secrete an enzyme called lactase (β-D-galactosidase) to digest it. This enzyme cleaves the lactose molecule into its two subunits, the simple sugars glucose and galactose, which can be absorbed.”

    Contrary to what you said, not much lactic acid is formed in the gut of a healthy infant.

    And all this philosophizing about the conditions way back when, how the fruits were back then-as if you know. Here in Texas, we have a wild Texas persimmon tree, and it makes an edible fruit that is very sweet. There’s not much to it because it’s small, and the pit is large, but Man o Man, it is sweet. And if it were less sweet, a person who depending on them would just eat more of them. And as far as competition from the birds, etc., well Man had plenty of competition towards getting animal food as well.

    Listen, I don’t say that everybody has to be a vegetarian. However, I am saying that, if you’re smart, you’ll realize that you have no good reason to eat a lot of meat. Maybe eat some in rationed amounts either because you like it or because you think you need it. But you fill up on plants.

    And to those poor folks, including Lierre Keith, who are crying the blues because they think they were ruined by vegetarianism, I say: there, there, now. Here in Austin, Texas, we’ve got a vegan fireman, Rip Esselstyn. And believe me he’s ripped. He looks like he could scale the Empire State Building with his bare hands. And when he’s not putting out fires, he’s competing successfully in high-level triathalons. Go ahead, tell him your sad story. Don’t worry; he’ll be compassionate; he’s a vegetarian.

  152. LOL seba! I’ve been eating ONLY meat for 8 months now, after being very low carb for a decade! I’m a 41 year old male and, now in PERFECT health. I have CONVERTED my doctor from a “low carb hater” to an ABSOLUTE proponent to the healthiness of meat (and saturated fat!).

    In 1999 I was 280 lbs, eating low fat and excersizing….now? 180 with little excersize and all meat.

    I guess I’m just the exception though……

  153. Paul,

    I’m sure there are healthy vegans in the world, just as there are healthy very-low-carb eaters such as myself. And who knows what shape you’d be in if you switched (as so many have) to a VLC diet? I will put my test results up against anyone – vegetarian, vegan or otherwise. It took a triple bypass to wake me to the dangers of eating whatever I wanted without regard to nutritional guidelines. And of course those guidelines — the Food Pyramid, the so-called “minimum daily requirements” and the rest — are poppycock, as I now know. I was a pre-diabetic with blood glucose hovering right around 120 when I saw the light. After eight months or so of VLC my A1C is 6, my triglycerides 66 and my HDL/LDL ratio 2. I didn’t have a weight problem, but I’m holding steady at 160 on a 6′ frame. I turned 74 this month and have never been healthier. I do eat some veggies, mostly the cruciferous ones, and some of the low glycemic index fruits, but it’s mostly meat, eggs, cheese, butter and nuts. Never bread, potatoes, pasta, rice, baked goods or anything with sugar.

    You make some good points, Paul, but they aren’t enough to make me change my ways. I’ve studied this situation extensively for the past year or so and I’m beyond convinced that Taubes, the Eades and the other low-carbers are dead solid correct (that’s a Texas term).

    This blog should be required reading for everyone in the medical field.

  154. Too bad all this fat and protein isn’t healthy for me, because it’s doing amazing things to my lipid panel.

    I started the 6WC on September 1 and “finished” on October 12, though I’m still on the all-meat portion because I like it and it sure seems to like me.

    Here are my cholesterol test results from right before I started and then again just last week after 6 weeks on the plan: (before/after)

    Total cholesterol: 223 / 206 (ideal is 200 and below)
    HDL: 59 / 65 (ideal is above 45)
    LDL: 140 / 132 (ideal is below 130, but if you’re triglycerides are low, this number is meaningless)
    Triglycerides: 121 / 45 (ideal is below 200, and the 45 is not a typo …. YOWZERS!!!!!!!!)
    Total divided by HDL: 3.78 / 3.17 (ideal is below 4.5)
    LDL divided by HDL: 2.37 / 2.03 (ideal is below 3)
    Triglycerides divided by HDL: 2.05 / 0.69 (ideal is below 2)

    As Dr. Mike has written, the triblycerides result and the triglycerides divided by HDL are the best predictors of cardiovascular disease.

    I suspect that my doctor prescribes statins because he has cholesterol posters all over his rooms. He’s gonna CRAP when he sees my numbers!!!!!


  155. I just wanted to thank Bryce for replying. Actually, just before reading your comment about Lierre Keith, I received a heads up from another list that had just done an interview with Lierre Keith. Don’t ya just luv serendipity. Here’s the link if anyone’s interested:

    After listening to the interview, Keith sounds like she was on a diet that was always going to cause her problems. She says herself that she consumed pretty much all carbs, very little protein and a lot of soy. I mean that’s obviously going to cause you problems.

    Actually, Keith is a little difficult to work out. She’s obviously intelligent and has researched her topic well but she is also extremely didactic and inflexible in her approach. And she says some bizarre things in the interview such as there are no plant-based sources of good-quality protein…

    I am interested to read her book but I hope it is not as frantically evangelical as she sounds in the interview.

  156. Come on Ralph! I’ve done the vegetarian gig, LONG ago….now I only eat meat….THERE IS NO COMPARISON AS TO WHICH IS “HEALTHIER”….That argument is moot.

    The compassionate argument is another story, but relative to one’s beiefs…not facts.

    You get me 20 “non roided” vegans, and I’ll get 20 “non roided” carnivores and we’ll line them up…I’ll show you the difference between “skinny” and “ripped”.

  157. So, Ralph, because breast milk is the proper food for human babies means that it’s macronutrient profile is ideal for adults? Breast milk is high in sugar and fat– it’s supposed to make babies grow and get fat. That’s not something that most adults aspire to do. And the fattest babies I’ve seen are those who’ve had nothing but breast milk for at least the first six months.

  158. Ralph, I do not live in the USA ,never have.
    I have many USA friends .
    They keep telling me stories about Texans.

    You have demonstrated they are right.

  159. It looks like I’m a little late to the comments section, but I have to say first off, it is refreshing to read such a well-written and researched article. It kept me interested when a lot of the academic stuff tends to make me gloss over (not a science buff).

    As a vegan, I am very aware of the important step animal protein had in our evolution, and deem it as quite necessary. I just cannot draw a parallel between how this could apply to the modern human. For instance, getting extra caloric intake was a struggle at that point in our evolution – even 100 calories a day – let along quality caloric intake and meat was a perfect solution to an animal that is at a relatively higher activity rate than the average modern human. For me to get and extra 100 calories a day all I need do is lick a cupcake wrapper, and I will not do as much in a day to burn it. Caloric deficit to the brain is not something I see as a modern problem – but perhaps I’m not understanding this correctly.

    Additionally, the source of mean our ancestors ate would have been very different that what we eat today. besides the obvious chemical intervention, cows, pigs and chickens as we know them today simply did not exist. The protein would be from smaller, leaner animals that were not factory farmed, and were not subject to feed from agriculture. A 90% raw food diet supplemented with 10% raw, lean, animal protein was what our ancestors ate, and I defy any meat-eater today to match that level of eating.

    But again, perhaps I’m missing the point. I know that veganism is right for me, not right for everyone, and I respect that. I think others should respect my choice as well, as I am a perfectly healthy, happy, intelligent and evolved human being. I believe the evolution is continuing and the specific needs for us at this point in our evolution may vary greatly from what they were in the period you’re discussing.

  160. What is your opinion on an all-meat diet? Do you think it is healthy? It seems like the logical end of all low-carb thinking to me, so I am curious.

  161. To George the Elder, you’re gambling bigtime by managing your weight as you are, and I must advise against it. Besides, I’m 5′ 7″, 135 pounds, eating vegetarian, and I’ll bet I’m leaner than you are. To George the Younger, at 21, and I can understand how important being ripped is to you at your age. But I’m 59, and although I’m plenty fit and strong for my age, I’ve got higher priorities than getting ripped. To Kathy, the point is that infancy is a period of rapid growth, and it is not supposed to be about getting fat. On the contrary, babies are developing bones, muscles, organs, etc., And if they can accomplish all that on 7% calories-from-protein breast milk, it’s hard to rationalize why human adults, who are not growing, should require proportionately more protein. And to Peter, this has nothing to do with me being a Texan, but there are plenty of Texans like me who are living proof that you don’t have to load up on meat to be strong, lean, and healthy.

  162. Interesting to read all you folks.

    A lot of belief systems, a lot of investment in being right, very little long-term ( I mean decades, not years) dietary practice.
    8 months ? I scoff.
    Let’s see after 30 – 40 years.

    I haven’t eaten dairy, industrial food, denatured fats or sugar for nigh on 40 years.

    Let’s see some real studies on non-dairy, non-sugar, no industrial fats – just wild meat and fish, foraged non-agricultural roots, tubers, sea-weeds and shellfish and fruits, nuts and berries.
    Or do none of you Paleo proponents really do this?
    Are you not really eating fruits and vegetables from farms?
    Are you not really eating pasture-fed modern selectively-bred cattle or farm-raised shrimp and salmon, antibiotic and other-laden aplenty ?
    I’ll bet most of you are.
    And that you binge on sweet foods regularily.
    That you crave grain, bread and other.

    There is virtually no science on modern Paleo-proponents.
    Sample sizes are ridiculously tiny in the meager 2 studies available to date.
    Do we use self-reporting instead?
    Your glowing testimonials, ever the sign of the snake-oil peddler.
    Or perhaps anthropologists should tell us via their reports on modern ” Paleolithic” peoples?
    Let’s discard their utter lack of training in diet and nutrition.
    While we are at it, let’s look at the lacunae in our understanding of paleolithic diet.
    Sample sizes are preposterously low and most discussion is speculation and extrapolation based on 4, 5, 6 skeletons of homo erectus.

    How dare you propose to feed 7 billion people on such skimpy data.
    Cordain on phytates or on rickets in Pakistanis in Bradford or Leeds is an example of the kind of weak-minded and specious argument to which I refer.

    Continue in your little self-congratulatory clique.
    I’ll bring roses.

    1. … i respect the differing opinions and people finding out for themselves what diet best fits their own physical/psychological/spiritual makeup – but mike’s reversion to “How dare you propose to feed 7 billion people on such skimpy data.” is simply not a good ending line for his argument. The issue is not what successfully supported the huge expansion of the available slave labor due to the necessities of the new world order of the agricultural fertile crescent, but what is ultimately healthy for our bodies based on our evolutionary history and biology. I personally don’t even care what the research and studies show (although i like when they agree with me… 🙂 ) but very simple logic with a basic non-biased view leads one to consider our dietary heritage (and the supporting indications of said heritage) in forming our current best-health diet. As the gorilla Ishmael so succinctly put it – this branch of humans (those veering off the hunter-gatherer path via dependence on agriculture) will end up being a sidebar in the ultimate evolution of the species – if we survive the “agricultural revolution” that is…

    2. … i respect the differing opinions and people finding out for themselves what diet best fits their own physical/psychological/spiritual makeup – but mike burn’s (above) reversion to “How dare you propose to feed 7 billion people on such skimpy data.” is simply not a good ending line for his argument. The issue is not what successfully supported the huge expansion of the available slave labor due to the necessities of the new world order of the agricultural fertile crescent, but what is ultimately healthy for our bodies based on our evolutionary history and biology. I personally don’t even care what the research and studies show (although i like when they agree with me… 🙂 ) but very simple logic with a basic non-biased view leads one to consider our dietary heritage (and the supporting indications of said heritage) in forming our current best-health diet. As the gorilla Ishmael so succinctly put it – this branch of humans (those veering off the hunter-gatherer path via dependence on agriculture) will end up being a sidebar in the ultimate evolution of the species – if we survive the “agricultural revolution” that is…

  163. LOL, being from Austin is not the same as being from Texas! Despite being the capital of the state, the people are not representative of most Texans. A popular slogan in Austin is “Keep Austin Weird.”

    I know, totally off topic, but I can’t help but defend my home state!

    Mike, I am a first time reader, and I will be back! I really enjoyed your summary of the article! Thanks for making it digestible, but not refining it too much!! I also spent way too much time reading the comments and your responses. Very interesting.

    I’ve been learning about and somewhat following the WAP type of diet for about a year now. I’ve heard some about the Paleo diet, but don’t know a lot about it. Worth looking into!

  164. @Kathy : Good point? Are you saying that formula babies are healthier then breast fed? If you think that so you need to speak to a real doctor they will disagree with you. Actually speak to a lactation specialist would be best.

    Dr. Mike:
    Your argument based on the book is we evolved faster by eating high levels of meat. Why has not lions and wolves evolved quicker? Why are indians so smart given most of them are vegetarian (history goes back as far as the 6th century)? Japanese are also vegetarian (well maybe pescatarian), and you see studies that on average they are smarter then westerners maybe over the centuries they have evolved quicker because they are doing it right.
    I so agree as Lindsey also explains in 13 reasons why we must eat meat:
    1. Eating meat is part of nature. We need to do everything the natural way. That’s why we never use modern appliances and computers or never slather chemicals all over our bodies in an indoor waterfall everyday. Besides, eating plant products is ENTIRELY unnatural.

    2. Eating meat will make you strong. And that’s why strict vegetarian animals such as pandas, horses, and cows, to name a few, are such weak, skinny, scrawny, anemic, helpless animals. (

    3. Meat is the only true source of protein. We all know that the millions (and probably billions due to lack of money to afford meat) of vegetarians through time just collapsed and died from protein deficiency.

    4. We should eat meat because it’s tradition. We’d be forsaking our culture if we didn’t. Where would we be if we ever forsook the time-honored traditions of slavery and forcing women to work in the home and denying them access to education?

    5. God told us it’s OK to eat animals. It’s in the bible! And that’s why our society heartily condones infanticide (1 Samuel 15:3, Psalms 135:8 & 136:10, Psalms 137:9), child sacrifice (Judges 11:29-40, Genesis 22:1-24), polygamy ( Genesis 4:19), slavery (Leviticus 25:44-46), and putting people to death for working on the Sabbath (Numbers 15:32-36). It’s in the bible, the ultimate moral authority!

    6. There is no point for animals existing unless they exist for us to use. And that’s why our raisons d’être would become completely null and void, and we would gladly submit to an intellectually and physically superior alien race who wanted to eat our own flesh. Might is right – the only valid way of life.

    7. Farm animals would quickly overrun the world if we didn’t kill them to eat them. It’s a miracle a few billion people had the space to exist before we started mass producing animals solely for meat by forcing them to breed or artificially impregnating them by the millions daily ( Animals were EVERYWHERE!

    8. Animals want to be killed to feed us. You can tell by the way they act when it’s time to die. We as humans, too, always scream in terror and thrash about and try to run when we’re having a good time!! (

    9. Our bodies are just like a carnivore’s! That’s why we have alkaline saliva to digest starches, which are strictly found in plants; a very long digestive tract so animal flesh, which has no fiber, can sit and rot for days; and very sharp teeth and claws for biting into an animal and killing it with our bare hands. We also can outrun most animals at our blazing top speed of ~25 mph and tackle them. We were designed to kill! Even our babies instinctually try to kill animals. ( , )

    10. Animals don’t have feelings. They are just big pieces of meat – big pieces of meat who just happen to cry and mourn for days when their young are taken from them ( or when they lose a companion of the same or a different species and excitedly dance when they see a beloved companion, human or nonhuman animal. Nope, all those are programmed, mechanistic, reactionary responses that are completely unlike our very divinely special human emotional responses.

    11. Americans are so very vibrant and healthy from our meat-centric diet, which is why we have the some of the highest rates of cancer, heart disease, and obesity in the entire world. We eat more meat than nearly every other country in the world, so we are the healthiest. What would we do without it?

    12. Most importantly, meat tastes freakin’ good. All of our morals are based on what our fleeting pleasures and hungers dictate us to do. That’s why we exalt serial killers, rapists, and pedophiles.

    13. Eating meat is a sacred personal choice and right. Just as deciding to dump loads of contaminated animal waste in someone’s backyard and to unnecessarily and inefficiently use up untold amounts of fresh water is our very own personal choice that has no ramifications on anyone else in this world – human or animal. ( , )


  165. Alex,

    One terrible flaw in the argument that animals can get big and strong on plant matter is this:

    Horses, Elephants, Cows, and other large ruminants get large and muscular while eating plants because the bacteria in their stomachs can digest the cellulose, and then the animals digests the bacteria. Humans Can NOT Do this. We have no bacteria in our stomachs, just our intestines. We can not digest cellulose (plant cell walls), which is why we call it fiber – it simply runs through you and you poop it out. The digestive track of a human is simply not the same as that of a strictly vegetarian creature. Period.

    Japan, as a country, has progressively eaten more and more animal fat since 1970, and their levels of heart diseases have fallen in that time. Also, Indians are not all vegetarian, and heart disease is FAR more prevalant in regions of India that are predominantly vegetarian. Non-vegetarian areas of India have less than one 6th of the incidence of heart disease, even though they smoke more. These facts I have just put out are easily verifiable, and if you care to actually do the research there, you will, I promise you, find them to be true. I did my homework, and found this.

    What makes you think Lions have not evolved? They are apex predators in their ecosystem, and their only threats (aside from poaching/human encroachment) are other lions. They have gotten really good at what they needed to get good at. So have we.

    Finally, I hate to mess with the stereo types, but are you saying that Japanese and Indians are smart simply because the ones who come to the west to participate in academically rigorous material are smart? What makes you think there aren’t just as many dumb Japanese/Indians as there are dumb Americans? Just because all of the Indians that I know personally are smart people, doesn’t mean all Indians are smart. It could be that only the smartest decide to come and excell in American Universities. This is a really weak argument here Alex. I’d expect more from someone attempting to dismantle the overwhelming evidence that we are meat eaters as a species.

  166. Alex, and I am being serious, on the basis of your last post you need serious psychiatric assistance.
    Please for your own sake seek it out..
    Best wishes.

  167. Dr. Mike,

    I’d like to ask a question regarding two statements you have made repeatedly and ask you to please reconcile them, because they seem to be at odds to me.

    Many times you have said this (I got this from one of your blogs, but don’t remember which one; I have it typed out and taped to my computer monitor; the highlights in all caps are mine, but the words are yours):

    “Optimal nutrition is plenty of good quality protein, plenty of good quality fat, and easy on the carbs. Remember, the human body requires protein and it requires fat; IT REQUIRES NO, ZERO, NADA CARBOHYDRATE.”

    You’ve also said the following things, which were taken from here:

    “Low carb dieters WHO CONSUME GREEN LEAFY AND COLORFUL VEGETABLES AND LOW-GLYCEMIC FRUITS are not at risk of osteoporosis (long-term bone loss).”

    “PCRM is on a little more solid footing when it claims that the Atkins Diet can cause bone loss, but PCRM misses the point entirely when considering the modified low-carbohydrate diet we and others recommend and that most people now follow. Studies going back almost a century describe the bone loss that can occur in people following a predominately meat diet. A diet high in meat alone creates a mild metabolic acidosis in the human body. This metabolic acidosis or excess acid created by the metabolism of meat has to be buffered or neutralized, which the body does by leaching calcium from the body’s storehouse of calcium, the bones. On a day-to-day basis the amount of calcium lost from the bones in this way is insignificant, but over a decades-long period of time can result in osteoporosis…. Most plant foods, other than grains, bring about the opposite metabolic situation; whereas meat consumption causes a metabolic acidosis, green leafy and colorful vegetables and low-glycemic fruits bring about a metabolic alkalosis. The reduction in acid-producing grain consumption along with the alkaline response of the very plant foods recommended on the modified version of the low-carbohydrate diet offsets and neutralizes the acidity from the meat so that there is no net metabolic acidosis and no long term bone loss.”

    Maybe I’m being dense, but it sounds like you’re saying that meat and fat alone represent the perfect food plan, but then you say you also need some leafy green veggies and low-glycemic fruit to be healthy.

    Does this mean that if you eat protein and fat alone, you could be at risk for osteoporosis in the future?

    Would you please take a few moments to respond to this?

    I’ve asked this same question on several discussion boards, thinking someone there is probably smarter than me and knows the answer, but so far no one has been able to explain to me how both statements can be true at the same time.

    Thanks so much!!!

    1. Isoflavones, which are in many plant foods, have increased bone density in experiments and drugs based on them are currently in use. In theory any plant phytoestrogen can have this effect to some extent, but isoflavones are the most studied. Oxidative stress can weaken the integrity of collagen-like bone protein (as with any protein) and antioxidants (including saturated fats as well as plant antioxidants) will protect against this effect.
      So it is not unreasonable to think that plant foods (other than starchy foods) prevent osteoporosis. Whether meat protein causes it in any digestible diet is another story. The needs of older people with low hormone levels may differ from those of the healthy young.

  168. Hi,
    I don’t really have a comment on the post itself, just a comment on my own eating habits. I guess you can say I’m a vegetarian but it isn’t for any of the silly reasons many people have for avoiding meat. After being exceptionally fit (athletic) and healthy (with a healthy diet) for the last 30 years, and a healthy cholesterol ratio, I still had a heart attack. I’m 5’10 and 172 lbs. After that I began to research deeper into the American diet. What I came up with is that I can’t trust anything. Before I ate very little processed food now I eat none. If it has an ingredient in it that I don’t stock in my kitchen I don’t buy it. I believe that meat and fowl are processed foods and I don’t trust how the animals are raised and fed. This is the only reason I don’t eat it. I was going to still eat fish until I read about the garbage patches out there in our oceans the size of Texas and now the oil spill among other crap in our waters. I don’t trust fish now either. I know that most vegetables are lacking also because of the poor soil they are grown in as well as the mas production of these crops etc but it’s the best I can do. I believe we are omnivore’s and meant to eat a variety of foods and if I could raise my own animals I would eat them. For now I am staying away from them. I do the best I can and eat whole eggs in moderation, the occasional whole milk (raw) fruits, veggies, nuts and legumes etc….you know the deal. I don’t believe the saturated fat myths but I also don’t make a habit of scoffing them up either…middle of the road for me. I’d rather whole milk than skim (I believe it’s healthier) whole eggs 3-4 times per week, healthy oils and the like. You posted a video and post about Jack Lalanne here at one time comparing him to Ancel keys. He seemed to do just fine being mostly vegetarian eating fish occasionally, never meat or fowl. He also ate only egg whites and went easy on fats. I suppose there could be other vegetarians out there like me. Not fanatics, just people who refuse to be duped into believing that the meat and chicken produced in this country still has the nutritional value it is said to have. I think it’s all grain fed garbage. Fish may be living in a chemical bath.

  169. Bruce,
    Are you a doctor? If so I hope you well in your boards with the idea that you have no bacteria in your stomach. While humans cannot breakdown cellulose, it is a good thing because fiber helps humans in many ways. I think you should listen to a lecture on sugar and how fructose is poison [].

    Now I know I had some of this coming since I quoted mostly from a vegan blog so. I will say I am Pescetarian, I believe in what tom( Tommy, June 5, 2010 at 5:51 pm ) has said about food in this country it is all junk.

    “The digestive track of a human is simply not the same as that of a strictly vegetarian creature. Period.” No kidding?

    Japan, as a country, has progressively eaten more and more animal fat since 1970, and their levels of heart diseases have fallen in that time. Really? Check this out think you have your facts wrong he got his facts from the Japanese government

    Also, Indians are not all vegetarian, and heart disease is FAR more prevalant in regions of India that are predominantly vegetarian. Non-vegetarian areas of India have less than one 6th of the incidence of heart disease, even though they smoke more. These facts I have just put out are easily verifiable, and if you care to actually do the research there, you will, I promise you, find them to be true. I did my homework, and found this. ( You promise is wrong again. Are you comparing apples to apples? If you look at the affluent vegetarians that can afford also the culture does not eat enough veggies and fruits as you may think because they are vegetarians does not mean they eat healthy []

    “What makes you think Lions have not evolved? They are apex predators in their ecosystem, and their only threats (aside from poaching/human encroachment) are other lions. They have gotten really good at what they needed to get good at. So have we.”
    Last i checked I cannot have a conversation with a lion…

    Finally, I hate to mess with the stereo types, but are you saying that Japanese and Indians are smart simply because the ones who come to the west to participate in academically rigorous material are smart? What makes you think there aren’t just as many dumb Japanese/Indians as there are dumb Americans? Just because all of the Indians that I know personally are smart people, doesn’t mean all Indians are smart. It could be that only the smartest decide to come and excell in American Universities. This is a really weak argument here Alex. I’d expect more from someone attempting to dismantle the overwhelming evidence that we are meat eaters as a species. ( Ok this is a stereotype that can be backed by facts ) well maybe not indians…

  170. I do not find this article conclusive by any sense.

    I was expecting more evidence to support the argument to be honest. The logic in this article baffled me as well.. heres two quotes out of it:

    “Based on the data and the argument they present, it is actually the opposite: we evolved to be meat eaters.”

    and then:

    “As I wrote at the start of this post, the evidence indicates that we didn’t evolve to eat meat – we evolved because we ate meat.”

    So what is it then Doc? You seem confused. For someone writing about intelligence, you’d think you would have noticed this gigantic contradiction!!

    Also, are you seriously trying to imply we more likely stem from a wolf than a primate ?

    “Makes you think more of a lean, rangy wolf or other slim-waisted carnivore, whereas the other two don’t.”

    Come on people, wake up. This article is just another pathetic attempt to justify human cruelty to other species. How is this any better than racism? This article is probably supported by $$$$ from some giant corporations.

    This article asks the reader to consider why we should even care for animals in factory farms… this is the sort of research carried out by scientists in WW2 Germany. It is discusting and vile and all involved should feel ashamed of their elitist mindsets and lack of care for other beings.

    The brain doesn’t even exist except for in our spiritual minds. The external world is an illusion mapped out through light information, that when compiled using form constants and recurssive mathematics appears to be material.

    We see what we believe is possible.. and this article confirms an ideology and stagnation of lower material vibrations for some. Others can see right through it for what it is.

    ***The sound of a rooster!!!!

    1. aaahhh, enter the vegan-zealot trying to dismantle intelligent analysis with “peta”-prod (like the cattle-prod but significantly less humane…)

      Kias dude (or dude-ette) – yer brain is screaming for some fat-soluble nutrients so it can start functioning normally again and follow a logical debate –

      and BTW – do you taste like chicken…? 🙂

      sorry, inside joke…

    2. When technically illiterate people cite “form constants and recurssive mathematics”, or for that matter any guff from the made-up world of particle physics, as if it somehow supports whatever prejudice they have or wishful thinking they want to indulge in, it just makes me despair.

      It is our fate on this planet to depend on the killing of animals, and it is people’s desire to hide from that inconvenient truth that has allowed the cruelties of factory farming, veganism and vivisection to flourish.

      How many wild animals died to make room for your soya beans?

    3. What is your proposal? To care about animal well being and uninterrupted life span more than about our own health? Are you insane or what? We are reading the content of the website because we are enjoying benefits of the meat based lifestyle and want to know more about all aspects of it from the doctor how already helped thousands of his patients to return their health. And who are you,somebody who cares about cattle more then about people? Then you found the wrong audience.

      1. My proposal is people start waking up a bit and realise that we don’t even need meat. and that to treat animals like slaves is barbaric and we have already evolved to a position where we can see think and feel this.

        I care about cattle as much as humans. This might be hard for your mind to grasp, but the seed of compassion takes a while to become a giant tree. I don’t expect you to at this stage.

        As for the audience, I dont think you are everybody on the internet that might stumble across this page?

        As for the soya beans George,

        My girlfriend and I are aware of the devastating effects of soy bean plantations and rainforest logging. This is why we buy locally grown Non GM soybeans wherever possible. This is a common attack on vegos/vegans.. do a bit of research at your local markets, and you will see this doesn’t have to be a huge issue.

        I will add that most of the deforestation concerning soy is what becomes livestock food?

        meat eaters.. you can become compassionate beings… even in this lifetime. It is all patterns.. and we have a conscious choice what we align with.

        If you love animals… don’t eat them? Its that simple. All of this justification just sounds like smoke surrounding the fire of a carnivorous appetite.

        There is something very disturbing and discusting about grown men eating baby lambs as though it is normal? When I really started waking up to what my own species was up to I spent several months feeling very sick. How our society condones murder to living beings is beyond me.

        If you eat meat can I judge you? No I can’t and I won’t. We all have free choice, this is all just my opinion.. I love animals and can’t stand to see them lined up like Jews in WW2 Germany and sent into slaughter houses so people can say: ‘yum’. Theres something really creepy about it. Think about it.

        Yes I am challenging peoples diets, and this will make them angry.. so let it be.. release your anger in a response and then sit still, and ask yourself whether you really care about anyone other than yourself. And if your wife, or child pops into your head.. then imagine how you’d feel if they become someone elses meal (in this day and age.. surely not!?!) YES.. this is happening, it is real, and these other beings could may as well be your grandmother or great grandfather (if you believe in reincarnation).

        Stinky/Vile/ Giant Factory Farms are not where my food comes from. Thank God for that. Go on.. enjoy your fine wine and expensive clothes..while you sit in that restaurant and pretend you know anything about class… then stuff some dead animal in your mouth.. some people like it with the blood dripping out the sides! I won’t have any of this vampire living.

        1. You know, I am not with you. Vegetarianism for me is a sort of cult which requires from people to have an unnatural and unhealthy life style.
          You have to understand that your rhetoric about vampires and eating members of family and slavery sounds as far fetched as ethical treatment of plants and crops. The futuristic novel by J.Updike came to my mind when he forecasts that in a future grass cutting for landscaping would be over due to the protests against unnatural and cruel treatment of grass (I wouldn’t mind eliminating of grass landscaping for different reasons, by the way).
          As long as you are not standing between me and my piece of meat – enjoy your cult.

  171. So we can lose weight faster by using our brains more?
    Perhaps mental hard work is more efficient than muscular exercise at burning calories. People who read a lot don’t seem to get fat as often as people who watch a lot of TV.

  172. I found this in Maimonides’ “the Guide for the Perplexed” which is the ultimate Old Testament reference book;
    “the commandment concerning the killing of animals is necessary, because the natural food of man consists of vegetables and the flesh of animals; the best meat is that of animals permitted to be used as food. No doctor has any doubts about this. Since, therefore, the desire of procuring good food necessitates the slaying of animals, the Law enjoins that the death of the animal should be the easiest”
    Various cruel and clumsy ways of harvesting meat are proscribed, including killing the young in the sight of the parent, or vice versa, “for the pain of the animals under such circumstances is very great. There is no difference in this case between the pain of man and the pain of other living beings, since the love and tenderness of the mother for her young ones is not produced by reasoning but by imagination, and this faculty exists not only in man but in most living beings”
    I get what he means; the hormones of emotions in animals – endorphins, serotinin, adrenaline etc – are the same as in humans, so their feelings will be recognisable to us. And if t’s not about intelligence, then a mouse or a possum or a bird does matter as much as any other animal, and quite possibly the feelings of even an insect are not completely alien.
    He also states that pork is banned for mainly aesthetic reasons (pigs are disgusting) but is also dirty and contains “more moisture than is necessary” (he should see modern processed bacon, which seems to be mostly water). And “the fat of the intestines” (suet? tripe?) is proscribed because it “makes us full, disrupts our digestion, and produces thick and cold blood; it is more fit for fuel”.
    Written and published sometime around 1190.

  173. The gut is a tissue with a fast rate of growth. Does this mean that, over time, the gut will grow larger in a human vegetarian (or shrink in a born again carnivore)? If this happens, according to the metabolic rate theory, either the brain will shrink, or, perhaps more likely, the metabolic rate will drop. Is vegetarianism today being misdiagnosed as thyroid deficiency and adrenal exhaustion?

    1. Hmmm. Interesting thought. I’m not sure the GI tract can grow or shrink a substantial amount within a human lifetime. But, I don’t know that for a fact.

  174. This doesn’t seem so farfetched – the liver and even the heart will grow enlarged if the demands on them stay elevated, so why not the gut?

  175. Thank you for yet another clearly explained, scientifically based article to give ‘food for thought’
    I love your blog and I carefully ignore your frequent use of the word ‘designed’ when you clearly mean ‘evolved’, but please, please don’t say ‘…further up the (evolutionary) tree…’ You know perfectly well there is no evolutionary tree with so-called ‘higher’ primates at the top and this is really a concept that should be destroyed at every chance – man is no more nor less evolved than any other living organism on the planet.
    I know you know this, I’m just pointing out an error of language :LOL:

  176. Yes, there are more dangers in our society than meat eating or NOT to eat meat, case in point:
    Shirley Miller attacked by dog in Garland Co.
    2:51 AM, May 7, 2011
    GARLAND COUNTY, Ark. (KTHV) — Charges have been filed against a dog owner after police say his pit bull escaped and attacked an elderly woman in her front yard Tuesday morning.
    A 72-year-old Garland County woman is recovering from a dog attack. The mauling is re-stirring debate over leash laws in the county.
    Shirley Miller’s family says her injuries are as bad as they can be. In fact, right now they say it’s touch and go. The good news is that she is out of ICU. However, the debate continues about whether this attack could have been prevented. Miller’s garden is just as she left it. Her neighbor Kelly Suit says she was tending to it when Garland County deputies say a dog brutally mauled her. “I mean I never thought this would happen in my yard,” says Suit. “I would speculate that probably the worst thing for a woman is for her face to be mutilated.” She’s being treated at St. Joseph’s Mercy. Miller’s granddaughter Ashlea Beene says a child likely wouldn’t have survived such an attack.

    “It’s as bad as you can imagine it,” says Beene. “Most of the trauma was to her head neck and throat area just as you would expect an animal to do.”
    Beene says her family is concerned about infection. Authorities say the dog’s owner Ricky Anderson, who lives across the street, didn’t have proof his dog was vaccinated. It one of two things deputies cited him for.

    For years people have debated whether Garland County needs a leash law. Currently there isn’t one, but there is a Vicious Dog Act and a Nuisance Dog Act.

    Garland County Justice Mary Bournival says she supports a plan to hold dog owners accountable if their pet viciously attacks.
    “We’re going to recommend a $1,000 dollar fine. Some people think that’s a little high, but that’s the fine you get for littering and I think this is a lot more serious than littering,” says Bournival. She says its time to take action so no one else is brutalized where they should feel safe. Some neighbors expressed concern about how long it took an ambulance to get to Miller. A LifeNet supervisor says they got there in 21 minutes, which he says is standard for that part of the county. The dog’s owner killed the dog after the attack. Bournival says the county committee on public safety is set to discuss implementing the $1,000 fine for owners of dogs that attack at the next meeting. The county attorney is already reviewing the proposal.

    HOT SPRINGS, AR – A pit bull attack lands one woman in the intensive care unit and she’s barely hanging on for her life.
    It was the first sunny day Shirley Miller had to garden in weeks when a neighbor’s roaming pit bull attacked.
    “She reached for a stick and she said before she could even get it he had her down on the ground,” said Miller’s granddaughter, Ashlea Beene as she sits by her bedside in the hospital.
    The pit bull attacked Miller, dragging her all the way to the end of the driveway where blood still stains the gravel.
    The owner of the dog, Ricky Anderson, stopped the attack by flinging his body over Millers. He shot the dog immediately.
    “She said its a good thing he came in because she was just about to stop fighting,” said Beene. Her grandmother remembers everything from the attack.
    But the 72-year-old will never be the same. Her face and neck are now mangled, her ear was ripped off and she could lose an eye. However, her family says the emotional scars will run even deeper.
    “People should – in this community as well as any community in the nation – should have the ability to walk the streets, be outside their homes on their property doing outdoor activities without being harassed by or attacked by free roaming dogs,” said Dan Bugg, the Director of Hot Springs Animal Control. They were the first on site to take the bite report.
    The dog had never been vaccinated for rabies and there are no leash laws in Garland County – leaving Miller’s family stunned and scared.
    “She’s just such a fighter and we’re so lucky but nobody deserves something like that,” said Beene.
    “I saw a lady who has a lot of challenges ahead of her. And a lot of pain and suffering to go through before she can get back to some normalcy in life,” said Bugg.
    The owner, Ricky Anderson, wouldn’t speak to us but his wife said it was a terrible accident. Test results show the dog did not have rabies, leaving animal control wondering what else could have cause such erratic behavior.
    Anderson is charges with not vaccinating his dog and for owning a vivious animal. His court date is set for May 24th at 9:00 at the Garland County Courthouse.

  177. so most vegatarians are doing right for the wrong reasons.

    fair and natural meat is very okay. But the way the industry provides the insane amounts of meat for the consumers is just to sick for words.

    caddle and other animals lifes from day of birth to the day hanging upside down are a bloody shame.

    and on the dogg story;

    if goverment allows dogs and other species to live among the people, they accept the fact that people get hurt.
    Its simple stuff, animals will “break free” at some point cause things DO go wrong and shit happens. and when that happens with a dog that sets his mind on a human that has no weapon -> the human is screwed. Humans are born weak, and in most cases stay very weak their whole lifes.

    dogs like pitbulls and german shepards (and many other animals that we keep near us) rip us apart like we are paper planes.

  178. All I can say is that my colitis healed when I gave up meat, dairy, refined grains and replaced them with fruit & veggies, much of them raw. And my doctor wanted to cut out a 10″ piece of my colon. I’m never going back to eating meat and I was as big a meat eater as anyone back in my 20’s.

    1. Jeff, funny how you give up two common allergens, dairy and grains, along with meat and blame the meat for your troubles.

    1. The sub title of this blog says it all: Humane Hypothesis of a Late Holocene Hominid. Humane in nice, and we all want to be humane, but there is no place for ‘humane’ in a scientific hypothesis. Science is what it is, humane or not.

      This blogger is guessing as what Aiello and Wheeler were thinking. I’ve spoken with Leslie Aiello, and I can tell you she was talking about meat and fat. And, as she told me, that’s why she and her colleague had such difficulty getting their paper published – it ran afoul of the low-fat zeitgeist at the time.

      All that aside, the most simple explanation of an hypothesis is probably the most accurate. It’s a lot easier to get plenty of calories from eating animals than it is from eating plants. Early man decorated caves with paintings of hunting and animals – not potatoes and brussels sprouts – so it is fairly easy to guess what was more important to our ancient ancestors.

      Plus, it takes an enormous amount of plant food to provide the calories needed for active humans. If you look up a red potato, a pretty nutritionally dense plant food, in the USDA Nutrient Database, you will find that it takes 19+ medium red potatoes to get the 3,000 calories an active human requires. The same 19+ red potatoes provide under 80 gms of protein, but it’s not a complete protein and absolutely no vitamin B12, an essential nutrient found only in foods of animal origin.

      Assuming for argument’s sake that the ETH is bogus, the stable isotope analysis puts paid to the notion that early man was a vegetarian.

  179. The blogger in question insisted himself that it would be flying in the face of evidence to claim that early man was a vegetarian: he wasn’t. As for the science about the ETH that he was referring to in his post, here’s the original article from Nature:
    Science is an ongoing conversation. If the latest scientific evidence refutes the idea that meat made us smart, then we should at least tentatively accept that refutation. Perhaps Aiello and Wheeler will have an even better response.

  180. I suspect that cannibalism was important in our evolution.
    And maybe we retained the genetic defect that prevents us making vit C so we could then spare the extra glucose for the brain (an extra 10g or so per day) during carb-fasting states.

  181. I guess I’m confused. How did we get meat when our brains were small and we were dumb in order for our brains to get bigger from meat? We couldn’t have made tools and organized hunts because our brains were small. There is no way our bodies allowed us to run down any meat and even if we did what were we going to do with it? We have not the teeth or claws to harm it in any way.

    Is there any other evidence that shows diets change a species?

    Why don’t all meat eaters in the world have big brains and are smart like us?

    Does this mean if we raised generations of apes on meat for a million or so years they should get smarter like we did? Maybe if we do for a couple generations we can measure some tiny progress to show that this would be the case if we were to extrapolate it out?

    Is it just possible that genetic mutation over millions of years was the cause of our brains getting bigger and our guts getting smaller and that this result caused us to be smarter, which allowed us to make tools and reason and hunt.

  182. This article commits the naturalistic fallacy. In particular “If we evolved because we ate meat, why would we want to stop now?” It also ignores that fact that humans evolved to live just long enough to procreate and raise those children. Not the 80 years we live today.

    The brain no doubt is larger because of meat. And that larger brain can now understand nutrition to such a degree that a meat-heavy diet is no longer necessary (and is not necessarily good for the environment).

    Evolutionary psychologists sometimes argue that rape was a productive evolutionary strategy. Does that mean rape is good? Of course not.

    So in summary, the article spends all its time buried in the detail of what is pretty obvious: brains in pre-technological society required meat. And then completely ignores what those brains can do now.

    1. There is plenty of evidence that early modern humans (and even Neanderthals) lived to advanced ages, so your first argument is spurious.

      The rape argument is off the charts silly.

      But thanks for commenting.

  183. Here is a slightly modified essay I wrote to an acquaintance on the subject of vegetarians versus meat eaters essay (because the human species is considered omnivore and vegetarianism is an option; but for arguments sake, I’ll use the term omnivore more loosely). It was a discussion on Facebook so I have now space to clarify certain points. I was replying to a series of postings this person had shared or commented on; it starts with a reply to a posting of a video of a Brazilian boy talking to his mom and protesting about the octopus on his plate.

    “He’s very cute, and as most toddlers, he’s going through that phase when they realize that humans eat animals, but most of us outgrow that initial shock, as we outgrow that phase of fearing death when we’re about 6 realizing our mortality for the 1st time, we also outgrow the shock of discovering how babies are made, and so on, those are natural developmental phases well documented in books we are familiar with. Of course, the mother is proud and considers it a unique phenomena, but it’s quite common in little children; to further stress their conflict, we take them to petting zoos, the farm, aquarium, we teach them not to pick flowers because they’re living beings, then we put a piece of octopus or chicken on their plate – it’s jarring! So I don’t think the kid is unusually sensitive or precocious, however, adorable. One article you shared mentioned, and I paraphrase, how ‘omnivores’ shove meat foods into their kids mouth and indoctrinate them; vegetarian parents and all vegetarian schools are doing just the same with vegetarian food. I think what this child’s mother needs to do is to appease her child and tell him it’s ok to eat or not to eat your octopus, humans eat animals and some choose not to; if we respect animals and feel gratitude for their sacrifice, if we use them only for our needs, it’s not a bad thing. To eat or not to eat animals is all within what people and other animals do, some animals eat animals. That would have been the psychologically right thing to do.

    But that brings me to another point speaking of plants as living beings, and I ask adults: Where do we draw the line? Plants are living beings too! It seems arbitrary to stop at animals, and planting millions of acres of grains and vegetables is not eco-friendly either!

    Speaking of ‘primitive’ or ‘primal’ instincts and actions, sex is also a violent act, and most of us seem to enjoy it, we coat it with terms of endearment “making love”, but in essence, it’s tension and violence, and it’s linked to the most primal of biological functions. I don’t see people protesting that sex is a ‘primitive’ activity well below our superior being status and posting a picture of a caveman next to sex quotes as saying “I’m better than this!”

    Guilt; I don’t feel guilty about sex or eating other animals, I fully embrace my symbiotic relationship with them, many are predators, so am I. Human rituals and ‘primitive’ cultures addressed this dependency on the execution of another animal with reverence and respect; we, yes, we ‘primitive’ people embrace nature’s laws of destruction to create life, we don’t all embrace modern destruction of the ecosystem and natural food chains, etc. In art one needs to learn to destroy, even what may be ‘good’ in order to create a connected deeper or ‘better’ ‘good'(better to be alive today than not, I think most would agree). I don’t feel guilt. I push myself against this intellectual but unfortunate development much enhanced by the Judaic-Christian tradition; it’s linked with societal control over the individual, so I don’t embrace guilt of eating meat. I embrace moderation, in my home we eat (checking sources of animal care and nutrition) red and white meat once a week each and fish or shrimp once, the remaining meals of the day and week are based on vegetarian, even vegan choices, an omnivore can eat everything. A cat starves in front of an apple, a cow starves in front of a chicken filet, I’d not starve under challenging conditions and my body is fit to decompose a snake in a desert, I’m grateful for this evolutionary course, we should all be grateful that our ancestors ate whatever they could find to stay strong and alive, for they brought us here. I embrace my grandparent’s decision to have only 2 kids; 2 people in a couple means 2 kids to replace them, but not overpopulate.

    So, let’s just agree to disagree and follow that quote you wrote “to each his own”, shall we? But it was not to ‘each his own’; you followed by sharing a list of bright minds that were vegetarian; for every 50 bright vegetarian, there’re hundreds of bright omnivore minds. One can attempt to instill guilt in others and they’ll stubbornly refuse to absorbed it, we can share images of cavemen or sharks with sharp teeth and we all know that they have nothing to do with the human condition except that they can eat us, we eat them too 😀 This debate I’m sure will go on for generations, but no one can prove that a good sensitive person doesn’t eat meat and a bad insensitive one does. Hitler ate raw vegetarian food the last few years of his life; it didn’t make him any more peaceful, and it certainly was not peacefulness that made him a vegetarian. And no, we’re not going to go into a petty debate if that is fact or fiction, we all know there’s plenty of absurd people out there who eat only one thing or another. Let’s also add that there’re plenty of unethical vegetarians that use leather products, buy clothing made in Asian sweat shops, lobby for criminal corporations, and so on and so forth. So I say to vegetarians, feel superior if you need to, I am a human only that, a human, don’t burden me with your subjectivity and sentimentalism over what humans eat or not, do whatever you want, stop preaching, and grow up!

    Namaste! (a proud POAB).

    (POAB = Pacifist Omnivore Atheist Bitch)

  184. That’s a great essay Malu. Thanks for posting it here.
    Actually being “better than (too pure for) sex” was a motive for vegetarianism at one time, and probably still is to a large extent, albeit subconsciously. Puritanical notions about food are a big part of the “healthy eating” delusion of all stripes.
    In fact I wrote about that here recently:

  185. So the anteaters prove exoskeletons aren’t good for growing brains also ?
    I know that they eat ants and termites and have a small brain for their bodies.

  186. Elephants may be interesting also, they are even mentioned as the second most intelligent animal on earth after us, and they are herbivores.

  187. It seems to me that humans evolved to me mesocarnivores, that is, omnivores who’s diet is about half animals and half vegetation. We don’t have the cellulose digesting abilities of herbivores, yet we get so many important micro-nutrients from plants (specifically fruits/veggies). We need so many nutrients primarily found in meat, and I mean MUCH more than most people think, though we are known to, at times, survive without any animal matter whatsoever. I thus interpret the evidence to conclude that modern humans are designed to eat animal and plant foods equally, but in dire situations, we can temporarily live enirely off one or the other.

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