Dan Lieberman, an executive officer of the ASPR and the organization’s treasurer, recently led an analysis of the Paleo diet using evidence from contemporary hunter-gatherer populations. The Paleo diet, which has become increasingly popular in the last few decades, recommends calorie ranges of 19-35% protein, 22-40% carbohydrates, and 28-47% fat, while also prohibiting dairy, grains, many starchy tubers and legumes, and foods with added sugar. These guidelines were originally based on an analysis of the diets of 63 foraging populations (Cordain et al. 2000), but Lieberman and his colleagues have challenged the extent to which this diet actually represents the eating habits of ancestral humans (Lieberman et al. 2023).
To assess the foods that paleolithic people actually ate, Lieberman’s study used 15 ethnographies that described the diets of 11 tropical hunter-gatherer groups. “Tropical” groups were defined as living in conditions that were nontemperate and non-Arctic, and for a population to count as hunter-gatherer, they could not practice agriculture, gardening, or animal husbandry. Some of the ethnographies that Lieberman and his colleagues analyzed dated back to the 1970s because hunter-gatherer populations are rapidly dwindling and it is not always possible to use contemporary records to study them. Drawing from the ethnographies, Lieberman’s study estimated dietary compositions by calories and weight. For example, they categorized all food as either an animal product, a plant product, or honey, and then calculated the proportion of total calories and weight that existed in each food group. They also scored each ethnography by its reliability, which was impacted by whether it took into account seasonal fluctuations and foods consumed outside of camp.
Lieberman and his colleagues found a great deal of variety in the eating habits of hunter-gatherers, and very few of the populations in their study had diets that were consistent with the Paleo diet. The variability they found was staggering; for example, in some groups animal products were the main food source, while other populations subsisted primarily on plant products. The findings point away from the notion of a “single ancestral diet” (Lieberman et al., 2023, p. 556) and ultimately suggest that the caloric ranges prescribed by the Paleo diet are an oversimplification and an inaccurate model of the ways ancestral humans ate.
References cited
Cordain, L., J.B. Miller, S.B. Eaton, N. Mann, S.H.A. Holt, J.D. Speth (2000).
Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. The American Journal of Clinical Nutrition 71(3), 682-692.
Lieberman, D. E., S. Worthington, L.D. Schell, C.M. Parkent, O. Devisnky, R.N. Carmody (2023). Comparing measured dietary variation within and between tropical hunter-gatherer groups to the Paleo Diet. The American Journal of Clinical Nutrition 118, 549-560.
Lieberman DE, Worthington S, Schell LD, Reply to RJ Klement, The American Journal of Clinical Nutrition, https://doi.org/ 10.1016/j.ajcnut.2023.09.026