Here's some good food for thought. (pun intended)


Critics often lambast the Primal Blueprint and other ancestral/paleo ways of eating for what they see as fatal flaws:

First, that we dont know what our ancestors were truly eating.
Second, that there wasnt just one paleo diet.
Third, that even if we could know exactly what our ancestors were eating, it doesnt mean those foods were the ideal foods; they were trying to eat whatever was available, not whatever was most nutritious or synergistic with their genome.

Before I address these, I want to make an important point. The anthropological record provides a framework for further examination of nutritional science; it does not prescribe a diet. It gives us somewhere to start so were not flailing blind men dropped off in the middle of a strange city.. That is why were interested in what early man ate (and didnt eat).

It may surprise you to know that I think the first argument is absolutely right. We dont know exactly what our ancestors were eating. There are no pleistocene food journal entries scrawled on a cave wall someplace, and many of the primary sources we can access €“ phytoliths (which indicate the presence of vegetal material) and stable carbon/nitrogen isotopes (which indicate the source of dietary protein) €“ require analysis and interpretation, thus becoming secondary sources. If you thought food frequency questionnaires were unreliable, try figuring out if the phytoliths found on Neanderthal dentition originated from the direct consumption of plants or the consumption of fermenting plant inside a recently hunted animals stomach, or whether the isotope analysis of African hominins from a few million years ago indicate diets high in grass seeds or diets high in grass seed-eating herbivores.
However, we absolutely do know what early humans did not eat:

 Industrial seed oils high enough in linoleic acid to crowd omega-3 out of their tissues.
 A diet where refined sugar made up either 17% or 15% of the total caloric intake.

We know these things because these foods either didnt exist until the late 1880s (seed oils like corn) or only graduated from expensive luxury item to widely-used staple food in the 1700s (white sugar).

As to the second argument, of course there is no one true ancestral diet with a strictly curated, specific list of dietary DOs and DONTs. Humans have managed to populate every barely hospitable nook and cranny of this planet. If living things grow, slither, crawl, flap, swim, or otherwise reside there, we will set up shop in order to eat them.

However, patterns do emerge. First, theres the aforementioned total absences €“ seed oils, sugar €“ plus a dearth of cultivated grains. Wild versions of grains existed (after all, the first agriculturalists needed something to domesticate), but theres little evidence to suggest they were major parts of most early human diets.

Second, theres animal consumption. We just love eating sentient, mobile organisms. Theres never been a traditionally vegetarian culture, and every hunter-gatherer population ever studied consumes animals (PDF).

Third, theres plant consumption. Plants are trickier than animals because they keep fighting back after youve killed (and sometimes cooked) them.

The third argument is a common one, and it takes many forms. The one I get a lot is that early man was a desperate scavenger, just barely skating by and eking out a diet of diseased rodents, chitinous bugs, tree bark, and lichen. Since he didnt €œknow any better€� and was just eating what he could without regard for nutrients, what early man ate shouldnt inform our dietary choices. Well, its a specious argument. Whether our ancestors were dumb brutes stumbling through life without ever considering what they ate (they werent) or unaccredited ethnobotanists with intricate knowledge of medicinal, toxic, and nutritious plants and animals (they probably were) doesnt matter in the slightest.

Lets say that natural selection adapts an organism to a given environment by selecting for an advantageous trait. What if the environment shifts, as they do, and the trait the original environment selected no longer works the same way? This is an evolutionary mismatch. It can happen with any environmental shift, like a change in diet.

Mismatches between an organism and its environment are core concepts in evolutionary biology. They arent controversial. In fact, evolution requires evolutionary mismatches, because mismatches represent selective pressures on an organism that lead to adaptations (which of course lead to more mismatches, and so on).

Its easy to see how diet fits in: if environment shapes an organisms evolution (via natural selection and evolutionary mismatch), and diet represents an aspect of the environment, then diet (in addition to many other environmental factors) must affect how an organism develops. I dont see how you can argue against that. You can argue that this specific food was or wasnt part of the ancestral dietary environment, or that Grok had no idea what he was doing, but you cant argue against the relevance of the ancestral dietary environment.

There were no €œideal foods€œ? Okay. Thats not the point. Im just establishing that there were simply €œdietary patterns that shaped the metabolisms, nutritional requirements, endocrine systems, and brains of the walking, talking, loving, pondering collectives of cells and microbes we call ourselves.€�

I dont know about you, but it seems like examining these dietary patterns might offer helpful clues for modern humans currently embroiled in a classic case of evolutionary mismatch. Mismatches are very interesting when youre a detached academic observing the trajectory of another species, but on the ground level, to the organism experiencing it, mismatches lead to diseases, pain, and suffering. Theyre awful.

Luckily, theres evidence that dietary changes are relevant. When zookeepers noticed the gorillas were getting diabetes and heart disease on scientifically-formulated gorilla chow, they said, €œHey, lets try providing a diet approximating the one these great apes might eat in the wild. Im thinking leafy greens, alfalfa, green beans, and tree branches.€� The gorillas thrived. So did the grizzlies and the elephants when placed on diets that approximate (rather than replicate) their wild diets.

Are we so different?

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