The Paleo Diet is Simply Right
Processed foods did not exist during the lion's share of evolutionary history--and this fact matters.
Photo Credit: Kie-Ker/Pixabay
Picture this: You throw a birthday party for your eight-year-old daughter. You bake her a chocolate cake with chocolate buttercream frosting—her favorite. You set up cupcakes and cookies and chips and candies for the young guests. A pang of guilt encourages you to also provide a large bowl of grapes as well as a plate of sliced apples. Two hours later, when the party is done, you find that the apples and the grapes were hardly touched at all.
From an evolutionary perspective, we can understand this all-too-common kind of situation quite well. And the answers are found in what is sometimes termed the Paleo Diet or the Paleo Solution.
What is the Paleo Diet?
When I first heard that the Paleo Diet (as described in detail by Robb Wolf and others) is considered controversial in some circles, I was surprised. To me, this approach to nutrition is obviously right. That said, I now realize that one should never be surprised by anything related to the concept of evolution as controversial. Looking at concepts, trends, and areas of inquiry that relate to evolution—including evolutionary biology, evolutionary psychology, biological anthropology, genetics, sexual selection theory, natural selection, and so on—I realize that controversy comes with the territory.
The Paleo Diet (see Wolf, 2010; Cordain et al., 2005) is an approach to nutrition that is based on the idea of evolutionary mismatch, a basic principle of evolutionary psychology (as described in my and Nicole Wedberg’s book, Positive Evolutionary Psychology and my book Evolutionary Psychology 101). Evolutionary mismatch is essentially the idea that when an organism finds itself in an environment that is mismatched from its ancestral environments—those environments that surrounded the ancestors of the organism during lion’s share of the evolution of that species—things can—and often will—go wrong.
Perhaps the clearest example of evolutionary mismatch in humans pertains to diet. Under ancestral conditions of human evolution—prior to the relatively recent advent of agriculture, approximately 10,000 years ago (an evolutionary blink of an eye)—the following facts relevant to nutrition were true:
Famine and drought were common
Starvation was a genuine hurdle to survival—it was a real possibility
Foods high in carbohydrates were hard to come by
Not a single bit of processed, post-agrarian junk food existed
Securing food required daily physical exertion
Under such conditions, a strong motivation to obtain foods that were high in carbohydrates—which were hard to come by for our nomadic ancestors—came to be selected because such a motivation was, under those conditions, adaptive. High carb foods play a major role in creating fat stores (which are very helpful during famine conditions). Anything that puts excess fat on one’s bones under famine conditions would be adaptive. A preference for the then-rare carbohydrates was, thus, selected naturally and, as such, this taste preference evolved and came to typify our species. This is why we like grilled cheese sandwiches, birthday cake, and pasta today.
In fact, perhaps the most vivid and gross evolutionary mismatch surrounding the modern human condition is this: Under current industrialized conditions, foods that are loaded with processed sugars are very accessible—and they often come in colorful packages (think M&Ms). These foods sell well—ironically—precisely because they were rare under ancestral conditions—they appeal to our tastes that evolved to anticipate food shortages. Further, food technologies have greatly out-paced biological evolution—we still have food preferences of our nomadic ancestors who experienced famine regularly. But the products of the food industry are advancing at breakneck speed—often without any understanding of human evolved psychology at all.
Why does this matter to the modern human condition?
In post-agrarian, or modern, societies, death as a result of obesity, cardiovascular disease, or Type-II diabetes is much more common than it is in non-Westernized, or nomadic societies (see Wolf, 2010). This is because modern societies provide nutritional offerings that are completely out of line with ancestral food offerings.
Our evolved food preferences, coupled with our modern technologies (such as the ability to make and sell Big Macs or delicious Shamrock milkshakes (hey, it is March…) for less than $5), are part of an enormous evolutionary mismatch that bears strongly on the nature of modern human health.
To my mind, the paleo diet simply pertains to the idea of eating the kinds of foods that were available to our pre-agrarian ancestors (fruits, cooked meats, fish, nuts—stuff that’s natural!). Our bodies evolved to “expect” these kinds of foods. Perhaps, more simply, the paleo diet pertains to avoiding unnatural, processed foods that would never have been available under ancestral conditions (cupcakes, pasta, cheese, Cracker Jacks).
Today’s Grapes and Apples as Simply Irresistible under Ancestral Conditions
Getting back to our birthday party example, there is a truly great irony to consider. Modern fruits and vegetables are the products of centuries of agriculture and artificial selection. In short, today’s average grape, cultivated by farmers and people in the food industry over centuries, is likely way better-tasting than any grape that was ever eaten by our ancestors prior to the advent of agriculture. Same goes for apples and bananas. And we now have seedless oranges and even seedless watermelons. On top of it all, we now have easy access to carnival grapes—which taste exactly like cotton candy (seriously—it is nuts!). That wasn’t always true...
So those grapes that are still sitting around at the end of the kid’s birthday party? They likely tasted better than any thing that any human prior to the advent of agriculture ever encountered. Think about that.
The Paleo Diet Simply Makes Sense
While specific versions of the paleo diet may over-emphasize some nutritional details, and there is always something to quibble about when it comes to science applied to the experience of being human, when we zoom out and look at this idea from the broad evolutionarily informed perspective described here, doesn’t it make sense?
To add to this scaled-down version of the paleo diet (or we can call it the more generically worded evolutionarily informed approach to nutrition, if we prefer), here it is in five words: Avoid processed foods. That’s it.
References
Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr (American Society for Nutrition). 2005a;81(2):341–54
Geher, G. (2014). Evolutionary Psychology 101. New York: Springer.
Wolf, R. (2010). The Paleo Solution. Victory Belt Publishing.
Note: This article is an unabridged variant of my Psychology Today piece titled The Paleo Diet as Straightforward and Obviously Right. I own the copyright to the content.