Almost annually, there seems to be a new diet being pushed by the media that proposes it will fix our weight troubles, reverse lifestyle-related diseases, and effectively turn us into ultra-fit, godlike versions of ourselves. Select examples of these diets are the Keto Diet, the Paleo Diet, the 80/10/10 Diet, Whole 30, and the gluten-free movement all of which recommend adherers stick to a specific percentage of each macronutrient and/or cut out specific types of food. Some diets (*cough* Paleo *cough*) do both. These six examples don't scratch the surface of how many diets are actually out there, but all fad diets have one thing in common: they push a cookie-cutter plan that claims to work for everyone. If only it were that simple.
If one wants to pull evolution into this (disclaimer, I always want to pull evolution into whatever 'this' may be), one will note that variation is essential for adaptation. If there is no variation, no trait can be 'selected' above the others (so no natural selection and no evolution). Like all other species who haven't suffered near extinction recently, humans exhibit a high-degree of variation. This variation becomes readily apparent when one considers populations that are indigenous to different parts of the world and have developed localized adaptations to best handle the environmental conditions that they face (i.e. enhanced lung capacity in Tibetan populations, etc.). Not surprisingly, since everyone needs to eat, dietary adaptations are common amongst human populations (Reference 1). If one were to use hunter-gatherers as an example, as I have been doing for the past two and a half years, one will see that the most consistent trait across hunter-gatherer diets is that they are extremely variable. In fact, the variation is dependent on the part of the world that each group inhabits, as I explored in my MA thesis.
It isn't surprising that hunter-gatherer diets are so diverse. Different kinds of food are available in different environments and in order to survive, local populations will need to be able to consume the food that is present in their environment. However, because hunter-gatherers are frequently used as models in public health (reference 2), there have been studies done to estimate the average hunter-gatherer diet (reference 3) under the guise that this is how Westerners should eat as well. Unfortunately, the amount of variation that exists amongst hunter-gatherer diets alone (to say nothing of other human diets) suggests that it is not appropriate to simplify hunter-gatherer diets into an average. Not to mention, the resulting diet from that analysis actually does not represent the hunter-gatherer diets that were analyzed, but more on this later when I publish my thesis results in a paper.
Practically, what does this nugget of information mean for you in terms of your nutritional goals? Maybe you want to lose weight, improve your athletic performance, or optimize your health. Do yourself a favour and ignore the latest fad, which likely advertises it can do all those things. Not only will you possibly do more harm than good by following whatever diet is most popular now (e.g. references 5 & 6), but humans exhibit too much variation for there to be one diet to rule them all. The diet may work for your friend, but not for you, and vise versa. The risk of wasted time is high. You'll be off to a far better start if you speak with a registered dietitian or nutritionist and to create a dietary plan that works with your specific physiology. Aka a real 'evolutionary-based' diet.
Works Cited
1. Fan, S. et al, (2016). Going global by adapting local: A review of recent human adaptation. Science, 7(354 (6308), 54–59.
2. Pontzer, H., Wood, B. M., & Raichlen, D. A. (2018). Hunter-gatherers as models in public health. Obesity Reviews, 19(December), 24–35.
3. Cordain, L., Brand-Miller, J., Eaton, S. B., Mann, N., Holt, S. H. A., and Speth, J. D. (2000). Estimations in Worldwide Hunter-Gatherer Diets. American Society for Clinical Nutrition, 71, 682–692.
4. Genoni, A. et al., (2019). Long-term Paleolithic diet is associated with lower resistant starch intake, different gut microbiota composition and increased serum TMAO concentrations. European Journal of Nutrition.
5. Smith, M., Trexler, E., Somer, A. J., Starkoff, B. E., & Devor, S. T. (2014). Unrestricted Paleolithic Diet is Associated with Unfavorable Changes to Blood Lipids in Healthy Subjects. International Journal of Exercise Science, 7(46), 128–139.