The tragically mislabeled “Caveman Diet”

Today, I would like to present a fresh perspective on the popular but vastly misunderstood “Caveman Diet”, aka Paleo, Primal, Ancestral, Evolutionary Biology diet, a way of eating that has been around for approximately 200,000 years, or about the age of the most recent genus of humans, homos sapiens.  It’s kind of hard to label this a “fad diet” if it strives to follow a pattern of food consumption that has sustained our species for hundreds of thousands of years prior to the development of agriculture.  Although I myself generally adhere to most of the concepts built into this diet, I shall nonetheless refrain from injecting observer bias into my observations and keep this conversation firmly grounded in solid science, presenting both the pros and cons of the theories upon which this diet is based.  My intention is to present an objective alternate point-of-view and avoid the temptation of “cherry-picking” studies that support my hypothesis, focusing instead on investigating criticisms in respect to this diet through the lens of evolutionary biology.  It also strikes me as noteworthy that calling this diet the “Caveman Diet” is akin to calling the wild game consumed by lions on the prairies of Africa the “Lion Diet”.

The basic premise of the Paleo diet is to focus on consuming only foods similar to what our hunter-gather ancestors had access to prior to the advent of farming and processed foods, i.e. fruits, vegetables, meat, seafood, and nuts.  The foundational logic underlying the evolutionary biology diet is that, by following the aforementioned nutritional guidelines, we are choosing a diet that is more in line with the evolutionary pressures that shaped our genetics, which in turn may positively influence health and wellbeing.  This diet lessens the body’s overall glycemic load, has a healthy ratio of saturated-to-unsaturated fatty acids, increases micronutrient density, and contains an optimal balance of protein, fat, and carbohydrates that helps preserve a healthy body weight and sufficient metabolic flexibility to support an active lifestyle.  As is the case with all efficacious diets, much of the success of the Paleo Diet can be identified as exclusionary in nature, i.e. attributed not as much to what it includes but rather what it excludes: fast food and junk food, hybridized grains, pro-inflammatory cooking oils, additives, preservatives, and generally anything produced by Monsanto!

In contrast to the “hunter-gatherer” diet, which dominated for 98% of human evolution, modern agriculture does indeed produce 10 to 100 times more calories per acre than the foraging posited by the Paleo diet, hence a more realistic solution (if not the healthiest) for feeding over 7 billion humans.  Over the period from 10,000 BC to AD 1, the world’s population increased exponentially about a hundredfold; estimates range from 40 to 170 times.  An accelerated rate of evolution may be a direct result of the much larger human population.  More people will of course have more mutations, thereby increasing and accelerating the opportunity for evolutionary change under natural selection, far beyond the speed at which such changes occurred in the pre-agricultural era.  The spread of rapidly expanding populations eventually outpaced the spread of favorable mutations in populations, thus for the first time in human history favorable mutations could not fully disperse throughout the species.  Two excellent examples of this are regional adaptations of salivary amylase transcriptors for starch digestion and the relatively recent ability to produce lactase in adulthood for the digestion of lactose found in cow’s milk.  In addition, natural selection pressures changed once farming was adopted, favoring distinctive adaptations in different geographic areas.  For example, farming, rather than merely reduced sunlight in Northern Europe has been hypothesized as having helped trigger pale skin in modern Europeans.  As illuminated by a 2007 study, almost all Africans and East Asians have one allele of the SLC24A5 gene, whereas 98% of Europeans studied had the alternate allele.  These data suggest that a “selective sweep” of evolutionary adaptations occurred as recently as 5,300 to 6,000 years ago, replacing darker skins with light skins at an astonishing speed.  This implies that Europeans had been dark-skinned for tens of thousands of years prior to this “emergency adaptation”.  Several decades ago, a researcher at Stanford argued convincingly that European hunter-gatherers, herders and fishers could have survived from the vitamin D content of their diet alone.  Only after farming took hold did it become necessary for Europeans to absorb more sunlight to produce vitamin D in their skin, having mostly replaced meat and fish with grains.

As for what these findings suggest about the evolutionary premise behind the Paleo diet, they clearly show that we are in fact complex combinations of both ancient adaptations and recent adaptations to global changes to traditional diets in the past 10 millennia.  Picking a single point in human history and trying to conform our diet to that particular time period, e.g. Paleolithic, may not be realistic, nor reflect our complexity.  That said, I still consider it a far safer choice to reach for an organic non-GMO apple than a bag of Doritos, regardless of any recent genetic adaptations to highly processed junk foods.  If we were fully adapted to consuming Doritos, we would not be currently mired in a global pandemic of obesity, diabetes, and heart disease, chronic diseases which were notably absent in our Paleolithic ancestors.  Speaking for myself personally, I’d much rather be eaten by a saber-toothed tiger than suffer for decades with debilitating health problems that could have been easily avoided had I respected the dietary and environmental inputs that my genes expected of me.

For further exploration of this fascinating topic, I encourage you to click on the link below to access an in-depth article published in “Scientific American” a few years ago:

https://www.scientificamerican.com/article/why-paleo-diet-half-baked-how-hunter-gatherer-really-eat/

Paleo-Caveman-Diet

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