Paleolithic man doubtless ate anything he could get his hands on that was even remotely edible, drank his water from streams, ponds, and probably even mud puddles as dogs do today. Of the many ways scientists have to unearth the actual diets of early ancestors, stable isotope analysis is probably the most accurate. Such analysis of ancient human remains show most were at least as carnivorous, if not more so, than foxes and wolves.

Compare and contrast our robust, nose-to-tail meat-eating Paleolithic forebears with today’s modern Paleo man, who drinks crystal-clear, reverse-osmosis-filtered, bottled spring water, wears five-toed Vibram shoes, wouldn’t be caught dead eating grain-fed beef, totes his almond-flour-based snacks, and always carries his baggie of nuts to nosh on.

Whenever I see these guys (or gals), it always makes me think of these lines from a great Kinks song:

“‘Cause he’s oh so good, and he’s oh so fine,
and he’s oh so healthy in his body and his mind…”

It might seem that I’m knocking the Paleo diet movement, but I’m really not. I do think it is vital to know what our Paleolithic ancestors ate, because over the millennia of our development as modern humans, natural selection weeded out those of us who didn’t do well on what was readily available then. So, in my view, it’s pretty important to know what was available then and to try to eat that as much as possible. But I’m not sure that Paleo guy, as described above, is eating as his ancient predecessors did. Especially when it comes to nuts.

I would like to go over a few issues I have with nuts as a Paleolithic food in terms of energy expended versus obtained and the fatty acid composition. And I’ll make a little detour to talk about our current obsession with grass-fed beef versus grain-fed beef.

A little biochemistry review

Before we go on, let’s recall the post right before the last one. We discussed how the FADH2:NADH ratio can be a switch flipping on a little insulin resistance. If the FADH2:NAHD ratio gets above a certain threshold, reverse electron transport takes place through Complex I in the mitochondria and produces a bit of superoxide, which drives a little local insulin resistance.

This insulin resistance is good for you because it diverts the fuel away from being stored in the fat cells and keeps it out where it can be burned. It also maintains blood glucose levels, which reduce or prevent hunger.

The goal is to keep the FADH2 up so the FADH2:NAHD ratio stays above the switch point. The breakdown of saturated fats produces the most FADH2, so saturated fats are a good thing.

Carbohydrates produce a small amount of FADH2, so they don’t flip the switch. Because of the double bonds in PUFA, they act more like carbs, don’t produce the levels of FADH2 saturated fats do, and so move directly into the fat cells to be stored instead of being used for fuel.

If you want to read more about the FADH2:NAHD ratio, take a look at Petro Dombromylskyj’s Proton series in his Hyperlipid blog. He has done all the heavy lifting on this idea, and the more I read about it and cogitate on it, the more I’m convinced he is correct.

Now let’s look at nuts.

What does it takes to make nuts edible?

Today most people purchase nuts from the store. Nuts come in cans and bags and bulk bins. Just about every kind imaginable and in all sorts of mixes.

When you get nuts like this, they provide a whole lot of calories for very little work. Which is why nuts are one of the big three foods I look at when patients don’t lose or stop losing weight: nuts, nut butters and cheese. All provide a ton of calories without much carb, so carb counters can keep carbs down while consuming a prodigious number of calories.

If you’re Paleolithic man out roaming the woods, nuts aren’t quite as easily available.

Nuts are seasonal, so you wouldn’t find them all year long. Granted, they can be stored, so a harvest of nuts could provide a portable source of food for lean times later on. But at what cost?

How many readers out there have actually picked and processed nuts? I can tell you, it ain’t easy. And it’s a lot of work for a fairly small reward. Unless, of course, you’re talking mechanization. Then that’s what you find in the bulk bins at Whole Foods.

But Paleolithic man didn’t have the Whole Foods option.

When I was a kid, I picked (picked up, actually – the nuts were usually on the ground) bushels of walnuts, but a few other nuts as well.

Those who have never seen a walnut in the wild may not realize they come covered in a tough green husk that starts to turn black after the fallen nuts have lain on the ground for a while. I can tell you from experience that it is a bitch to get these husks off the actual nuts within. The green color of the husks gets all over your hands and it has a really pungent, chemical smell that takes time to get rid of. Pick walnuts off tree or the ground underneath, and you’ll have green, smelly hands for a day or two.
Walnuts on tree
The husks are extremely difficult to remove. When I was a kid and we picked walnuts on the farm, we would put them in burlap bags, throw the bags full of walnuts on the dirt road, and run over them with the pickup. Back and forth, back and forth. Over and over to breakdown and start to tear away the husks. Then we would take the nuts out of the burlap bags and remove the broken up husks by hand, a task I loathed. Not only did it take forever to do, but bits of husk always got under my fingernails and my green hands smelled like walnut husks for days.

Once we had stripped the husks off, the actual walnuts inside were kind of a slimy black color. We left them to dry, which took a day or so. They never looked like the walnuts in their shells shown below. Those are chemically processed.
Walnuts in shells
Hand processed, they’re kind of a dirty dark brown.
Walnuts husked
After going through all the above husking and drying, you can then crack them and work to extract the little bit of nut inside. It’s a long run for a short slide to do all this by hand.

Since Paleolithic man didn’t have burlap bags and a pickup truck, I doubt he could extract enough calories from nuts to make them worth his while. Especially since the nuts available to him would have been even smaller than the ones on our farm, thanks to modern hybridization.

So, in my view, our ancient ancestors probably didn’t get a lot of their calories from nuts.

But you can get a load of calories from the nuts of today with very little effort. This is my hand holding an ounce of modern walnut halves representing ~185 calories.
I can tell you that I could (and have) throw this back as one mouthful. A couple more handfuls of these modern walnuts over a day would add between 500 and 600 calories.

Nuts versus grass-fed beef

I want to look at nuts in terms of fatty acids content, but before we do that, let’s take a moment to shift gears and discuss the fatty acid content of grass fed beef versus corn-fed beef. The reason for this digression will soon be illuminated.

Much has been made of the difference in the ratio of omega-6 to omega-3 fats when comparing meat from grass-fed beef to that from corn-fed beef. There is a difference, and a lot of people turn up their noses at corn-fed beef, because the O-6 to O-3 ratio is higher than in their grass-fed compadres. This is all well and good, but how much are we really talking about here? Remember, we don’t eat ratios. We eat fat, some of it of the omega-6 variety, and some of it omega-3.

I’ve thrown together a few graphs to demonstrate. The first shows the O-6 to O-3 ratio of grass-fed vs corn-fed beef along with the actual amounts of these fats in 100 gm of beef (about 3.5 ounces). Data for these slides came from here and here. The first source got data from the USDA Nutrient database while the second did their own testing, showing values better than the USDA.
O-6_O-3 content beef
Okay, from this graph, it is clear that we get more O-6 fats from corn-fed beef.

Remembering the post on the FADH2:NAHD ratio and the first part of this one, O-6 fats tend to reduce local insulin resistance whereas saturated fats increase local insulin resistance. So if we eat O-6 fats as part of a mixed meal, we will find ourselves in the situation in which insulin sensitivity is high at the level of the fat cell, and O-6 fats (PUFA) are pouring into the fat cells along with glucose.

Not the greatest situation if you’re looking for weight loss.

For grins, here’s a graph showing the difference in the O-6/O-3 ratio for grass-fed vs grain-fed beef.
O-6:O-3 ratio beef
So, from the data on these slides, it seems we’re better off with less overall O-6, which makes the grass-fed beef the obvious choice, right?

Well, maybe. But before we decide, let’s consider the walnuts again.

Below are two more graphs I’ve created showing the O-6 to O-3 ratios of walnuts (most nuts are about the same with macadamia nuts, which contain mainly monounsaturated and saturated fat, being the big exception) as compared to grass-fed and grain-fed beef and the amounts of O-6 and O-3.
PUFA ratios walnuts and beef
Walnut Fatty acid content
The O-6 to O-3 ratio of the walnuts looks pretty close to that of the grass-fed beef. And the fatty acid content appears to be not all that different.

But I’ve resorted to a little trickery. Not anything any researcher worth his salt wouldn’t do if he wanted to make a point. It is an accurate representation of the data after all. Nothing dodgy. If the readers want it to make sense, they’ve got to sort it out for themselves.

Well, I’ll sort it out for us.

I fiddled with the 2nd graph above by changing the scale so that at first glance it would seem that the amounts of O-6 and O-3 in the walnuts were around the same as in the beef. But such is not the case.

I set the graph showing the amounts of fat in beef to show in milligrams whereas I set the chart for walnuts in grams. A mere order of change in the magnitude of a thousand.

So, if you compare the amounts of omega-6 fats in the same amount of walnuts (calorie-wise) as in beef, you’ll find that 3.5 ounces of walnuts contain over 218 times as much omega-6 fat as does a 3.5 ounce chunk of grass-fed beef.

That’s not a mistake. Over 218 times more!

The graph below shows the amounts using the same scale for both the beef and the walnuts. The grass-fed cattle are on the far left; the grain-fed in the middle; and the walnuts on the right. As you can see, compared to the omega-6 in an equivalent amount of walnuts, the omega-6 in the beef barely registers.
FA content of beef and walnuts same scale
Since there is over 200 times more omega-6 in walnuts than in grain-fed beef on a per weight basis, in order to get the amounts to be similar in the chart below, I had to compare 3.5 ounces of beef to one half of a single walnut.
Half walnut vs beef
All it takes is three walnut halves to equal the amount of omega-6 fat in a ten ounce grain-fed steak. Remember, I could throw back the handful shown above (14 half walnuts) in a single bite, so that would be the equivalent to the omega-6 found in a three pound steak. And as I mentioned, I could easily throw back multiple handfuls over the course of the day, if I allowed myself.

It somehow feels less noble checking out at the grocery store with your 16 oz grass-fed steak, which will save you about a third of a gram of O-6 fat (as compared to grain-fed), while throwing in the 16 oz bag of walnuts that will add over 200 grams (almost half a pound) of omega-6 fat to your diet. (This comparison is between the amount of omega-6 avoided by selecting grass-fed over grain-fed.)

Helps to explain why nuts are one of the biggest weight-loss killing foods around. Tons of omega-6 fats driving the FADH2:NAHD ratio down and running these fats easily into the fat cells. Eat sparingly. And think of how much work Paleolithic man (and I in my youth) had to do to get just a handful of walnuts.


Note: I owe credit to Pete Ballerstedt for directing my attention to the small differences in omega-6 content of grass-fed and grain-fed beef as compared to the amount of omega-6 fat found in nuts.  Especially important was this presentation.  It was the realization from Pete’s presentation combined with Petro’s Proton series that made me start thinking about why nuts (and nut butters) prevented weight loss.

Photo at top by MiguelZalazar on Unsplash


  1. Excellent post, and probably why I’m struggling a bit with getting back on track with a low carb diet. Thanks for that.
    I do have a question, though. Does the label “USDA” denote grain fed beef?

    1. I think it just means it’s been inspected and graded. But having said that, I’ve got to admit that I’m not up on all the USDA regulations.

  2. Dr. Mike,
    In the first graph, I believe the y-axis is mislabeled – it should be fat in mg/100g. The values are pretty close to what I see in the USDA DB for 90/10 hamburger crumbles, pan browned. I see .428g total PUFA.
    And I agree completely – nuts are deadly to weight (er, fat) loss.

    1. AAAARRRGGGHHHH!!!!! Once you pointed that out – and you were absolutely correct – I had to go back in and fix it, which was a multistep process that took forever. Thanks for the heads up. Pain in the rear though it was, I’m glad at least that it’s now correct.

  3. Why only walnuts. There is a huge variety of nuts ( look at the democratic party). Sorry couldn’t resist.. Almonds, Cashews, macadamia, filberts. They can’t all be the same. Why not do a piece on the whole nut family. This one is good but too narrowly focused.

    1. Most, but not all, nuts have a lot of PUFA in them. You can Google them or go to the USDA database and look them up. If I get the time, I’ll see if I can find some sort of summary and post it.

      1. I was going to add that I recently swapped walnuts for pecans after focusing on trying to get more MUFA. Walnuts have something approximating 13 g PUFA, 3 g MUFA per ounce, while pecans almost have the reverse (6 g PUFA, 12 g PUFA). This basically means hitting not just one but two goals – not just lots more MUFA – which I want – and also LOTS less PUFA – which I want to minimize.
        I love the taste of walnuts but I’m going with pecans (happily I like them, too) now based on this fatty acid info. But may cut down on all of them after this blog post. This is still much much more PUFA than even a grain-fed steak. Thanks for posting.

        1. Being a Southern boy, pecans are my favorite nuts. But I’ve cut back on them because despite their containing mainly MUFA, they still have a lot of PUFA. Can have as much as 40 percent.

        1. I grow up in a cold climate, collecting filberts in a forest. Sure, it is a hard to overeat that way.

  4. Are you psychic? I just gave my son an $18 bag of roasted pistachios (I was attempting to add some potassium to my diet and I don’t eat fruit or veggies); a carton of Hawaiian roasted macadamias ($14 for 24 oz. at Costco) and some chuck steaks now that I’ve finally determined that I dislike tallow and beef. Nice Jewish girl loves PORK! So it’s intermittent fasting, pork chops, pork belly, pink salt (it’s delicious), water and happiness.
    When I took the time online to study the nutritional profiles of various nuts, the phytic acid issue alarmed me. So, aside from an ex-boyfriend, my life is free of nuts.
    Once again, you may look like George Clooney but you think like Einstein.

    1. “…you may look like George Clooney but you think like Einstein.”
      Well, I guess that’s better than the reverse. 🙂

  5. Thanks for this post!
    Have stayed low carb consistently for decades but was kind of stuck on “good” instead of “great” results in recent years.
    Kept reading and started messing around with some changes.
    Stopped using almond flour based recipes (e.g. “wheat belly” pancakes, “stuff I make my husband” pizza) because of concern about omega 6 levels. Delicious recipes but I’m sure the omega 6 levels would register sky high on your charts.
    Became more diligent about avoiding vegetable oils, and avoiding soy in general, and avoiding the way fast food restaurants process oils these days. Still use olive oil on occasion.
    Greatly increased use of Fage full fat or 2% fat plain yogurt adding our own strawberries, blueberries and a few walnuts as a topping.
    Stopped eating almonds. They are too good. Like crack cocaine to me so I just stopped buying them. Rarely eat walnuts by themselves any more. Too good. Too easy to overdo it.
    Increased my saturated fats greatly, especially from meat. Did reduce walnuts to maybe an ounce per day.
    Voila … became unstuck. So some combination of the above did the trick.
    A consolation for cutting back on nuts … in some local grocery stores I can buy a pound of bacon and a pound of grass fed beef for less than a pound of walnuts.

    1. Thanks for the dietary history. I’ve heard this same thing from many people. I, too, am a sucker for nuts. If they’re there, I eat them. So what I have to make sure is that they are not there. So I purchase my pound of bacon and pound of grass fed beef instead.

  6. This is fascinating! Thanks for the informative post. I’ve been a long-time visitor to your blog, and came across it after watching “Fathead” maybe 5 years ago. I’ve seen all the science and it all makes intellectual sense to me, but it has taken me FOREVER to escape the calories-in-calories-out paradigm and realize that so much of what I’ve been taught is just flat wrong. I’ve always been a “moderation makes the most sense” type person. After much research (and regaining ten or so pounds post-kids that I can’t, this time, blame on any of my babies) I jumped into low carb this week. I’m on day three and so far, I LOVE IT. For my entire 41 years, as long as I can remember, I’ve struggled with reactive hypoglycemia. I would eat “normal” food in smallish portions (I’ve never been one to eat a huge plate of food at once), and within 1.5-2.5 hours after eating, would have a major blood sugar crash. I quickly learned (in my late teens) how to recognize the signs and eat something small, nothing huge, to ward off a crash. So most of the time, I’ve been able to “manage” this condition without any major weight gain (my highest lifetime weight, and then only during a pregnancy, has never exceeded 155; normally I’m around 125-135, but even that’s not ideal for my 5’2″ small frame). My doctors have never really been that concerned or proactive about it either, because (I presume) my weight was fairly normal, BP normal, and all glucose tests (pregnant and not) normal. Fasting glucose and all other labs also normal. But I’m so, SO tired of being at the mercy of needing to eat, having to plan/know I’ll need to eat again in 2 hours, etc. I felt like I had tried absolutely everything. The first time I tried anything remotely low-carb, it was the Zone diet (because I felt like that was sort of “easing into” low carb, where full LC seemed too drastic to me then). It was horrible. I now know why – the Zone had way too little fat (and probably too few calories in general) for me. It turns out that LC/HF is the perfect balance for my system. It was the fat component that I was missing while trying to do the Zone. Now that I am doing just LC and high-fat, I’m having no trouble whatsoever with hypoglycemia, and that’s nothing short of a literal miracle for someone with my history. Thank you, THANK YOU for continuing to publish and analyze the science so that people like me (who grew up in the height of the low-fat and margarine craze) can finally get it through our heads that it’s safe to try low carb, the world won’t come to a screeching halt, and in fact it might just solve our problems. I’ve never EVER gone three days with zero hunger and zero hypo. It’s absolutely amazing to me.
    So, first I just wanted to say thank you for that! Your influence and writings, more than anything else I’ve read, have led me to be willing to try LC/HF. I picked up David Ludwig’s book on your recommendation and devoured (ha!) that. It all makes so much sense.
    More to the point of this post, now that I’m 3 days in, I’m starting to look at what I should be eating for snacks (not that I need many, but more of a just in case that I can stick in my purse). I had thought nuts would be a good choice, but I’ve been keeping up (for the most part) on your notes about PUFAs. And that might explain why, when I adopted the habit of eating walnuts as a snack at my desk job (before kids), I immediately gained what seemed like every.single.fat gram from those nuts – straight to my rear. At least it wasn’t straight to my gut, but still! Ugh! So I’m thinking I’ll do as you suggest and moderate the nut intake!
    Thanks again for all you (and MD) do for all the rest of us. You’re making a difference – one stubborn CI-CO person (in my case) at a time!

  7. And now I want Grandma’s black walnut and oatmeal cookies.
    We ran over the walnuts, too, sans burlap bags because we did it in the drive, not the road. Then picked walnuts all winter because idle hands are the devil’s playground.

  8. I think hazelnuts might be an exception, there is evidence these were roasted in large quantities in early neolithic Britain, which would have meant they were made into a foodstuff that lasted some time. Also, nuts can be collected in very large quantities by the small burrowing animals that hunter-gathers still hunt, so collection doesn’t depend exclusively on human effort.
    But our ancestors probably only had access to edible nuts for a small part of the year, apart from those in tropical climes, such as the San bushmen.
    A diet based on mongongo nuts is in fact more reliable than one based on cultivated foods, and it is not surprising, therefore, that when a Bushman was asked why he hadn’t taken to agriculture he replied: “Why should we plant, when there are so many mongongo nuts in the world?”

    1. Thanks for the info. Looks like the mongongo nuts have a fairly high percentage of PUFA, though.

  9. Great post and education (I bet you had to walk five miles to school and de-tassle corn, too) on what you really have to do to nuts to get at them and why they look so perfect in the grocery story. Best thing here for me is seeing the marginal difference in Omega 6 levels between grain-fed and grass-fed meats. That little difference I can lose no sleep over. I also recently removed nuts and cheese as I continue on, and feeling much better without the nuts (not so much without the cheese…). I can eat pistachios, cashews, and peanuts (which I think are all the most HC of the “nuts/legumes”?) until the cows come home and want their cut, but most tree nuts don’t taste all that great to me and usually leave me feeling a bit ill, which I’ve always thought was weird. I’d just been eating them to get in more fat. Really hate eating anything that feels like an Rx rather than food, so this also is a relief.

  10. Eating too many nuts not only makes me gain weight but gives me a stomach ache. They’re expensive, too.
    Where my grandmother lived in southwestern Missouri, people made crafts out of black walnut shells. I used to glue fabric to the bottoms of the shells to make turtles.

    1. Hey, southwestern Missouri was where I lived when I was a kid and where we ran over the walnuts in a burlap bag. Where did your grandmother live?

      1. Iantha, near Lamar, Barton County. There were walnut trees, trumpet vines and mulberry bushes, a big garden out back, and the neighbors raised hogs across the street. Grandma put water in the Frigidaire so it wouldn’t taste like sulfur and the sky turned orange at night just before the fireflies and june bugs came out.

  11. Hazelnuts were certainly used in Mesolithic Britain and Ireland. One reference from Irish Archaeology says they were particularly plentiful at the Mount Sandel site (presumably this would be from pollen evidence in the soil) and thinks they “may” have been an “important” food source. They say they can be stored for up to a year “after curing”. (I don’t know what curing would mean in this context: perhaps they’d keep better after being dried or something.)
    It seems people drew on an impressive number of different food resources in the Mesolithic in Ireland: fish, fowl, wild animals (particularly boar), and wild plants, including nuts, water-lily seeds and crab apples.

  12. O3:O6 in beef is such a red herring, so to speak, and a constant battle when people obsess about it but think nothing of smashing down nuts by the truckload.
    >The ratios are substantially higher, but the conclusion is “not a rich source” of omega fats – you’d need to have 10+ “servings” of beef to get anywhere close to the O6 in a single serving of chicken, and 30-40 servings to get the O3 of salmon. (numbers vary wildly in reports so that’s a ballpark number-from-the-air but you get the gist)
    >You’ll completely smash that ratio simply by having a snack on most nuts or anything with seed oils in it or swing it the other way with a small piece of salmon etc. If the only thing you ever eat is beef there might be a need to concern yourself, but so far I’m not convinced.
    >In the end it’s kinda like obsessing about the carbs in an egg when you’re having it on toast.

    1. “In the end it’s kinda like obsessing about the carbs in an egg when you’re having it on toast.”

    2. We’ve started to cut down on chicken because of the high O6 content. We’re trying more beef (grass fed, if we can get it and it’s not insanely expensive), pork, lamb (again, grass fed if we can get it). We also buy locally raised chickens when we can (less O6 content, supposedly).
      I still eat some cheese and yoghurt, and we encourage our kids to eat cheese (rather than anything with carbs). The cheese does not appear to kick me out of ketosis, nor does it appear to cause me to stop losing weight. But I don’t eat that much of it, and I still perform a lot of intermittent fasting (which for me helps probably the most).
      I’ve also switched to some fish per week, and some fish oil too.
      Ever think about doing an article on the kitivans? If I hear another discussion of the kitivans and how they eat a ton of carbs per day (and apparently 50+ percent of them smoke), yet have ideal insulin and blood sugar values, my head’s going to explode. If I had access to the original studies, I’d read them, but I cannot find the original studies online anywhere.

  13. Oh yeah, same same with the harvesting of nuts scenario:
    >I had an almond tree as a kid, unfortunately what we have now though is ridiculously easy access to overdo them. When getting them from the tree it takes hours to harvest even a handful and then you’ve somewhat depleted your tree, good luck stuffing yourself on them – such nuts in such an environment are nothing more than a rare snack.
    >Right now though I have 1kg of the things sitting in my cupboard that I got for $5 bucks, the reason I don’t just sit there and pig out is a purely reasoning one as I don’t like the idea of spiking myself with excess phytic acid or fiber – and I know I couldn’t trust myself to just eat “a handful” when there is a ton of them there.
    So yeah, if I’m socialising and there’s nuts and snacks I’m on board, but I find they have no place in everyday life.
    Maybe cos I’m nuts enough already…

  14. Aside from the fat content, inside food there’s much more to talk about. I’ve always frowned at the commercial versions of the paleo diet that recommend “healthy” nuts and seeds. Ironically, one of the many reasons to avoid grains, is about their antinutrients content, but they seem to ignore that the antinutrients content in nuts is even higher than in grains. And other touted seeds have an high antinutrients content as well.
    On the other hand, discounting grass fed beef vs grain fed only for the omegas ratio is unfair and not accurate. It’s a lot about micronutrients content and the fat used as toxins warehouse that makes eating fatty cuts of grain fed beef not a very good idea.

  15. I’m confused. I’m trying to lose weight and keep my heart healthy and most of all keep my cholesterol down (to keep the specialist happy, as I’ve stopped taking the statin.)
    I’ve started taking omega 3 (330 mg DHA 270mg EPA) and I do eat nuts inc walnuts, a little each day.
    Is the omega 3 ok? Should I stop the nuts (which I have to avoid getting crisps for my husband)?
    Would be really grateful for an answer. I really enjoy your articles, they are most helpful.

    1. I can’t really answer specific medical questions online. I’ve never seen you as a patient, and I don’t know your medical history, so I would be shooting in the dark. I, myself, take a krill oil softgel daily, which approximates what you are taking. I would think the nuts would be better than crisps, but it would depend upon how the crisps were prepared.

  16. PS my triglycerides are ok, also the HDL LDL rstio, so should I worry about the LDL figure anyway?

  17. It is to laugh. I don’t eat walnuts because of the smell I associate with the husks. And that was 50+ years ago. I will eat a few pecans if and only if they are fresh AND someone else has shelled them.

  18. For the lay public it is almost impossible to apply the science to day to day eating. Even this article is hard to get a grasp on. Are walnuts vastly higher in fat than beef or are they just vastly higher in unsaturated fat than a steak? Do your charts show the whole fat content of steak or just the small portion that is unsaturated? Is Omega 3 vs Omega 6 not an issue with saturated fat? For example, I like eggs, bacon, chicken and steak. To the extent that I don’t give a hoot about heart disease can I eat them to my hearts content and balance out the O3:O6 ratio with a handful of walnuts?

    1. I eat eggs, bacon, chicken (if I have to) and steak and don’t feel the need to balance my O6:03 ratio. I do take a krill oil softgel daily, but not to balance anything.

  19. I have come to the same conclusion. I grew up around pecan trees. They don’t sound as labor intensive as walnuts, but still quite a bit of work.

  20. I don’t understand why you compare nuts vs grass-fed beef. When you are going to write about “paleo grass-fed beef”? Do you really believe that paleo men ate beef?

      1. And bison, which are sufficiently close to being the same species that they freely interbreed with modern cattle. (And used to be more numerous in North America than cattle are today.)

        1. I don’t think there is evidence to say that beef (or predecessor) was significant in the diet of early man. I would like to see references

  21. Wow, thank you, this was eye-opening! I’ve used nuts as a “must have something salty and crunchy” crutch, to avoid going for chips, while being mindful of what you’ve written in the past about patients who haven’t lost weight b/c they were going to town on the nuts—I weighed and counted and was diligent. But if I eat nuts, I don’t lose weight (don’t gain either, so long as I keep to my LC ways, which is the purpose of the nuts).
    Would celery and seasoned cream cheese (like Boursin) be better to use as the anti-junk crutch?

    1. Re the celery and cream cheese. I think it would be much better. That’s in fact what I do. Not on the celery, but just a bit of cream cheese.

  22. This makes a lot of sense, the high Omega 6 content driving the FADH2:NAHD ratio would have evolved as an adaptive mechanism for packing away a load of seasonal excess food prior to winter (seeds are also relatively high in O6).
    you may not have these but undoubtedly something similar – high carb nuts! Probably the worst of both worlds.
    I have memories of helping my aunt pick her Kentish Cob Nuts – a type of hazel – on her farm, and getting the nutcrackers out at Christmas, which slowed things down considerably compared to buying a packet and hurling them back. Oh and trying to extricate chestnuts from their prickly shells which was easiest when a bus had run over them.
    I eat toasted almonds with fish on the basis that the O6 and O3 probably cancel each other out, and cashew nuts in chicken or prawn curry, but yes it is VERY easy to overreat the little buggers if you have a bag of them.

  23. Just curious–what supplements besides Krill oil do you and your wife take on a daily basis? And do you take some others weekly?
    Thanks for the outstandingly informative blog.

    1. She takes more than I do, and she takes them more regularly. And I don’t even know what they all are.
      I take daily (when I remember) a krill oil, a magnesium, an alpha-lipoic acid, a carnityl, a curcumin and a vitamin D3 5,000 IU during the short days of winter. No vitamin D in the summer.

      1. Hi Dr Eades,
        I’m very curious. What is your reasoning for the ALA and how many milligrams?

          1. Oh I don’t recall a mention of ALA specifically but maybe I need to read it again. I do grasp the general concept of the ratios and the switch (being not based on the ratio per se but the total amount of O-6 PUFA). Well, I think I do.
            I suppose what I’m getting at is this. Are there supposed to be any cases where folks took some ALA and some benefit happened? E.g. the folks who have AD and do a little better taking some fish oil supplement with EPA/DHA, or something like coconut or MCT oils. I’m just talking about common anecdotes.
            Or is it purely for the better variety in fatty acids as seems to be the case with your taking krill oil? (I may be wrong on that assumption, too, however.)

          2. I think I understand your question. If you are asking if EPA/DHA acts like ALA in terms of throwing the switch, I think the answer is yes. But EPA/DHA absolute values are much lower than the typical intake of ALA, especially if the EPA/DHA is taken in as krill oil. The fats are hooked up differently in krill oil than they are in fish oil, so you get the same potency at a much lower dose in krill oil, which is why I prefer it.

    1. The blog post would have been as long as War and Peace had I tried to include every nut in existence. Pecans can contain up to 40 percent of fat as PUFA, so they’re not all that great either.

      1. These ratios are really important information. I wish I had time to study all this in depth and enough knowledge of biochemistry to assimilate everything. But I just learned why my weight loss stagnated–cashews as a back up when our monastery cook puts high carb foods on the dinner table. By the way, don’t overlook acorns in hunter-gatherer diets. And do sunflower seeds fall under the same profile as nuts?

  24. Add to that the fact that many nut husks are either extremely poisonous (cashews, IIRC) or when ripe rapidly become toxic due to fungi (black walnuts) and I expect nuts were more avoided than eaten, especially since the husk *looks* like the edible part, while the nut inside the shell is non-obvious and invisible unless you smash it.
    Further, aside from being sharply seasonal, the volume produced just isn’t that great, and nut trees tend to be scattered, rather than the major component of a forest.
    Also, I wonder what the long-term effect would be of a diet high in nuts. Many decades ago the Yahi Indians (of northern California) were a subject of study due to going extinct within modern times, and one paper put forth a theory that white incursions weren’t responsible (the tribe being already in sharp decline by the time Europeans arrived), but rather that (having migrated fairly recently from a more-bountiful environment) it was a result of their shift to using acorn meal as their primary food, with consequent early kidney failure. By the time whites arrived, the Yahi were a tribe of children raising children; there were few adults and fewer old people.

    1. Acorns can be eaten safely if soaked before preparation, I know that it was a staple of the diet during WWII in the town where I grew up in Italy. Not that people liked it, just that it was edible. That said a better way to eat them is to feed them to the pigs, and get the best prosciutto and pancetta ever. Chestnuts were a great source of calories up and down central Italy for generations, I don’t think the difficulty of getting to the nut-spiny shell and all, really made much difference to their consumption. However most nuts were eaten in season, not year round.

  25. I’m not sure that saying “hunter-gatherers wouldn’t have eaten nuts because …” —where I can see this discussion going—holds water. What matters is not what someone might think they did but what they did do. And for that it’s necessary to consult archaeological remains and/or the ethnographic record.
    (But it is, of course, valid to say: “Whether or not they consumed such-and-such a foodstuff, I don’t think it’s right for me in my context.” And this is where the analysis of the ?-3/?-6 ratio comes in.)
    We know Native Americans, for example, made use of several species of nuts. Interestingly, Indians in Virginia made a drink called Powhicora (a kind of “nut milk”) from nuts such as hickory nuts. It’s not a valid parallel to imagine oneself cracking nuts with nutcrackers one-by-one and trying to get a whole kernel out, because that’s not what they did. They smashed the whole nut up—kernel and shell—then added water and allowed the shells to sink to the bottom:
    In general human beings are pretty good at thinking up ways to save labour.
    On the issue of the meat, for what its worth I think “grass fed meat” would better recommended on other grounds than it’s ?-3/?-6 ratio (or its CLA content). There’s a nexus of animal welfare issues, working conditions and ownership issues, environmental and landscape issues meeting and interacting in this area that, it seems to me, are of far greater significance. (This is where the work of people like Allan Savory comes in.) Apart from anything else, the use of antibiotics not even for disease but for animal fattening, which is legal in some countries (including the U.S.) is a huge potential problem, both in terms of these getting into the environment and getting into the meat. Sometimes it’s not what’s in your meat, but what’s not.

  26. I think I commented earlier on an “unreply” email so here goes again. 🙁 I’m surprised and kinda shocked about the nuts. Haven’t attempted Paleo but I watch carbs best I can. I know now why my scales are stuck…I rely on nuts for snacks instead of reaching for sweets. (which is really what my sugar-addictive taste buds want anyway)
    I struggle now staying on low carb more than I ever have. Am so interested in reading more of what you showed about the FADH2:NADH ratio. I have to read and re-read the technical parts but would like to learn more about how to keep my husband and myself healthy. I always thought about getting retirement age and eating out all the time…no cooking…HA. We’re here now and I only think about the junk in the food when we do eat out.
    Sometimes I search and read so much trying to find ways to keep prescriptions at bay that I confuse myself. But I’ll definitely keep reading your blog — thanks so much for what you do!

  27. Two issues here.
    First, the caloric return for effort is, in sources I’ve seen, very high – the only vegetable food competitive with hunting large bodied game. Personal stories don’t cut it here. It’s also to be noted that a very large proportion of the San hunter gatherer diet came from nuts.
    Second, it is the ratio, not the absolute amount, of omega 3s and omega 6s that matters. The brain needs both. For most people, this boils down to getting enough omega 3s, not limiting omega 6s, so the walnuts are still looking pretty good there.
    I am a bit surprised at the very low proportion of omega 3s in your statistics on grain fed beef, though. I’ve seen other numbers that are not as bad, and now I’m wondering what the difference is.

  28. Oh poo! I just finished one of my “staple” meals of mixed salad leafy greens, 3.75 oz can wild Alaskan sockeye salmon, balsamic vinegar, olive oil, salt & pepper, and about 1/8 to 1/6 cup sliced almonds mixed in. The 3.75 oz of salmon isn’t enough to satiate me without the nuts. Sometimes I’ll add shredded cabbage or broccoli slaw to bulk it up. I used to use a larger can of salmon but worried that the extra protein might raise blood sugar too much. No diabetes but overweight. I just used the last of my sliced almonds, and now think I won’t replenish them. I’ll try adding a bit more salmon, or perhaps a piece of crumbled bacon (now we’re talking).
    Mike, thanks for the always eye-opening information. Growing up, I didn’t have to shell nuts, like you, but I did have to walk 3 miles to school, uphill, both ways!

  29. As ever a great post (especially when referencing Peter – the best?), but one thing is wrong for me – your photos (except the first one) and descriptions of walnuts…
    Where I live (France, Southern part of Massif Central), our walnuts (on the tree and when they drop to the ground) look just like your first photo, but then there is not much in common, especially that ‘dirty, dark brown’ – ours emerge from the husks on their own (no effort on our part) and look more like your second photo, albeit much darker in colour (& smaller).
    Another difference is that when we crack open our nuts, we tend to get small pieces and very rarely those ‘perfect’ half nuts. Finally, I think our nuts may be smaller.

    1. Thank you for saying this Kevin. I’m often in South west France, and our walnuts are just as you describe them.

      1. We have a walnut tree in our back yard. Although the nuts fall of the tree looking mostly like the ones in the first picture (just darker and dirtier), they’re still a lot of work. I spend 1 to 1 1/2 hours each day in the fall for about 2-3 weeks collecting the walnuts. Then they need to be washed, parts of husks that are still stuck there removed, and thoroughly laid out to dry because they attract mold easily. Once dry, I give mountains of them away to friends and family, who – I know – never appreciate the work that has already gone into them. That still leaves enough for my husband and me for an entire year. For my favorite gluten-free bread recipe (also made with almond meal) I crack walnuts for an hour. For all that, we appreciate the foods I make with them even more, even if no-one else does.

    2. A bit of a web search suggests that most walnuts in Missouri are black walnuts. Walnuts in Europe are likely to be English walnuts. English walnuts also have a better fatty acid profile than black walnuts do.
      For those who believe that new world plants are necessarily nonpaleo – because there weren’t any humans in the new world in the paleolithic – black walnuts would not be paleo even if old world tree nuts are.
      There is also the theory that tree nuts are okay because once you’ve gotten past the shell, you’ve gotten past their protective mechanism. By that theory, black walnuts would be paleo, even if the effort to extract them would have deterred paleolithic humans had they been there. But that theory doesn’t address whether a specific species of nut is good for you, just whether they are purposely evolved to be bad for you.

  30. Thanks Dr Mike, great read making great sense. I eat nuts sparingly and except for roasted pistachios and macadamias, always soak the raw nuts in salted water for 8+ hours to minimize/eliminate their anti-nutrients/nutritional inhibitors. Then I place them in a dehydrator to thoroughly dry, get them crisp, then store in the freezer to avoid rancidity. I can get nauseous eating unsoaked walnut halves they are so hard to digest. Also, I always choose grass fed & finished beef, not for a more favorable n6/n3 ratio but for the increase in many other micronutrients and higher CLA content, as stated in an earlier comment. Cows are herbivorous ruminants meant to eat and ferment grass. Period.

  31. Given that macadamia nuts “contain mainly monounsaturated and saturated fat,” and they ok for snacking (in “moderation,” of course!)?

    1. In my view, they are better. In moderation, of course. MY problem is that I have trouble eating any kind of nut in moderation. If they are handy, I’ll eat them. A few here, and a few there, then, before I know it, the bag is empty. So I try not to keep them at hand.

      1. Thank you thank you for this post – love it. I have been gaining weight and I know it’s the nuts. The problem is everywhere we are told to eat “more nuts and seeds” so my lizard brain reward system justifies the nuts and then no matter how much I try to limit my intake they open a gateway to overeating. I’ve got to abstain from them. To be honest it’s not that they taste that great it’s just the soothing hand to mouth action of eating.

      2. I have a query about macadamia nuts. I have somewhere in the back of my memory the these nuts are a source of vitamin K2 – is this correct?

  32. Thank you, Mike, for a great treatment of this topic. Looking forward to your presentation today. I’ve got a little something for you from southern Missouri…

  33. Well done Dr. Mike….., and nice to see you blogging again… least a little bit.
    So with this info, I think both my spouse and I will give up on the nuts and keep them out of the house altogether, as you are doing.
    P.S. – Did you see the piece about President Obama, said to be very disciplined and parsimonious with his intake of almonds? No more that seven….., or thereabouts.
    It’s almost as if he may have been looking at your blog. 🙂
    P.S. When the heck is your pplp update coming out? I think we all may need it sooner rather than later. 🙂
    Wil / Judy

    1. Did not see the piece about the President’s intake of almonds.
      Working on the book when we can. Life keeps intervening.

    2. Actually, he may eat more than 7 almonds every night. It was a joke that was blown out of proportion by the media, as usual.
      In any event… he looks pretty thin for a guy who eats nuts every night for a snack!

  34. Great information as always. Can’t wait for the new edition of “Protein Power.” I think cheese is my problem re stalled weight loss. All cheese?

  35. ” And think of how much work Paleolithic man (and I in my youth) had to do to get just a handful of walnuts.”
    Couldn’t the same be said about tracking and hunting wild game? Paleolithic man couldn’t walk a few feet to the kitchen and have pounds of meat readily available 365 days a year…

    1. True. But I would think tracking and hunting wild game would provide more of a bounty for the time spent than a handful of little nut shards.

      1. My point had to do with calories. I was thinking that since cheese (high saturated fat) and nuts (generally high omega 6 ) both cause stalls — the common denominators are that they are calorically dense, readily available and quite delicious — hence very easy to overeat. Any food that one considers delicious can cause overeating in some individuals. Interesting stuff on this by HL Newbold. Too much focus on merely carby/sugary foods becoming “addictive” by how they stimulate pleasure centers in the brain. This can happen with any food or drink. Paleolithic man did not eat 3 squares or even daily. So I think omega 6 in nuts is being singled out a bit unfairly. But if one is intent on paleo reinactment, then one could also try eating bugs and fasting etc. I think worrying over one’s omega6 to 3 ratio could cause unnecessary food obsessing and stress. Wolfgang Lutz has interesting thoughts on how obsessing over diet can be truly counterproductive in his biography by Bracken.

  36. So, how do we reconcile that with this recent study?
    And studies such as these:
    “There are claims that energy-dense foods are especially problematic for weight loss and maintenance. Nuts are among the most energy-dense foods consumed, yet the literature consistently documents little impact of their ingestion on body weight.”
    “…there are consistent evidences from epidemiologic and clinical studies of the beneficial effects of nut consumption on risk of CHD, including sudden cardiac death, as well as on diabetes in women, and on major and emerging cardiovascular risk factors.”

  37. This article contains so many flaws and subjective bias that it would take another article to set this discussion on a cognisant track.
    Sooo many uses of the word ‘I’ just doesn’t strike me as objective discourse.
    The obvious bias toward the validation of eating meat is off putting to say the least.

  38. Hi Dr. Eades, : )
    I really enjoy pecans, too. I try to eat a lot of variety for my nutritional needs – leaning on the lower carbohydrate side.
    P.S. You really should do the “Million Dollar Challenge” challenge, Dr. Eades. You will win for sure and make the calorie zealots look like TOTAL idiots. It is basic particle physics that energy and matter are as different as heaven and giraffes and should NEVER even be paired in one’s mind together. Have them demonstrate that “energy” is some substance or , better yet, even “stuff” or ANY entity of any sort whatsoever that exists itself in this universe- tangible , or intangible ( It’s neither tangible , NOR intangible- ONLY a number, property, concept, abstraction). Energy is not, itself, ANYTHING at all. I can back this up. Feel free to use this information.

  39. My people have eaten acorns forever, and they are not a big deal to process. Besides, what else will you do with the kids when you’re all huddled up inside come winter?
    I would be interested to hear they break out nutritionally.

    1. The acorn fatty acid profile is thus:
      16:0 13%
      18:0 2%
      18:1 58%
      18:2 27%
      So, 58 percent is monounsaturated fat and 15 percent is saturated fat, leaving 27 percent as Omega-6 fat. Not too bad overall.
      Plus, acorns usually drop in the fall, so it would make sense that they would fatten people up for the winter. But, acorns are not a food we were particularly designed to eat. Take a look at this article about a pre-agricultural group of people who ate primarily acorns. See what their teeth looked like. Had we been designed to eat acorns, our teeth would have held up a little better I would imagine.

      1. Since we’re still here to protect our ancestors from the grave robbers, no one has done any extensive examination of their teeth, so I can’t say whether they had cavities. However, my great grandmother (born in 1880’s) grew up eating acorns and still had her own teeth to the end. Of course, we didn’t eat only, or even primarily, acorns. We were big on fish and venison.
        Still, if you define “paleo” as what hunter-gatherers ate, I can’t imagine how acorns would not be part of it. I can’t imagine anyone not utilizing such a store-able and nutritious food item.

      2. I don’t know how the ancestors’ teeth were, but my great-grandmother (born in 1880’s), who grew up eating acorns, still had her own teeth to the end. Of course, we never lived primarily on acorns, we ate a lot of fish, deer, elk, etc. Especially lots of salmon, who hold a high place in our culture.
        If you define “paleo” as what hunter-gatherers would have eaten, I would think that acorns would surely be a part of it. I can’t imagine anyone bypassing such a store-able and nutritious food item.

  40. The “walnuts” you were shelling were black walnuts. The picture of the store bought walnuts were English walnuts. Totally different types of nuts. We had a black walnut tree when I was young. Yes, they are very difficult to shell but the taste is so much better.

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