By Cliff Harvey
There is a significant body of evidence that most hunter-gatherer populations have until recent times subsisted relatively healthily (notwithstanding mortality from infectious diseases, warfare or predation unrelated to diet), with a significant absence of metabolic disorder on a low carbohydrate diet.
The Inuit for example are often referenced as a population that has, by necessity utilised a low carbohydrate diet for millennia, containing a significant amount of protein (approximately 377g of protein per day), equating to around 47% of the daily calories (with 46% coming from fat and carbohydrate providing a mere 7% of calories) (1).
Likewise Aboriginal diets in Australia have been extensively studied. The traditional Aboriginal diet is low in carbohydrate and promoted the maintenance of lean body weights and minimised insulin resistance. When Aboriginals transition to a modern western diet high in carbohydrate and refined fats, the incidence of metabolic disorders, obesity and diabetes rise markedly and interestingly a temporary reversion to a traditional hunter-gatherer lifestyle causes ‘striking improvements’ in carbohydrate and lipid metabolism. (2)
Some of the analysis of hunter-gather diets may be slightly flawed as there is not always attention paid to animal-part choice when food selections are taken into account. This may have the effect of suggesting a greater protein and/or carbohydrate intake and a lower than actual fat intake. It is well known that hunter-gatherer populations will prioritise fatty tissue (such as bone marrow and organs) if able, in order to avoid spoilage of organ meat, provide the maximum calories (and micronutrition), but perhaps most importantly to avoid the dire metabolic consequences of protein overconsumption (3).
This is congruent with both the hunter and scavenger dominant theories of human food acquisition, especially as it appears that both hunting and predator confrontational scavenging are likely to have provided a large amount of the food for early humans (4). Fresh kills by both hominids themselves and other predators would have provided organ tissue and bone marrow—both high in fat (and fat soluble vitamins), with the relatively lean tissue of wild game meats being a secondary fuel source to the fattier, and thereby more calorically and nutritionally dense tissue of organs and bone.
It must be noted however that there is considerable variation in hunter-gatherer diet with respect to macronutrient content. 229 hunter-gatherer diets from around the world were analysed using plant-to-animal subsistence ratios. A high variance in carbohydrate intake was found (approximately 3%-50% of daily calories) with carbohydrate intake being inversely associated with latitude i.e. with extremes of latitude especially in Northern Tundra environments are higher proportion of animal derived foods and hence protein and fat are consumed. However the authors noted that independent of the local environment the range of energy intake derived from carbohydrate in most hunter-gatherer populations is lower than the current recommendations for healthy humans. (5)
1. Sinclair HM. The Diet of Canadian Indians and Eskimos. Proceedings of the Nutrition Society. 1953;12(01):69-82.
2. O'Dea K. Westernisation, insulin resistance and diabetes in Australian aborigines. Med J Aust. 1991;155(4):258-64.
3. Speth JD, Spielmann KA. Energy source, protein metabolism, and hunter-gatherer subsistence strategies. Journal of Anthropological Archaeology. 1983;2(1):1-31.
4. Domínguez-Rodrigo M. Hunting and scavenging by early humans: the state of the debate. Journal of World Prehistory. 2002;16(1):1-54.
5. Ströhle A, Hahn A. Diets of modern hunter-gatherers vary substantially in their carbohydrate content depending on ecoenvironments: results from an ethnographic analysis. Nutrition Research.31(6):429-35.