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.
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.
Hand processed, they’re kind of a dirty dark brown.
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.
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.
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.
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.
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.
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.