Ancestral diets and metabolic health: what traditional populations tell us
Traditional populations eating high animal-fat diets showed remarkably low rates of metabolic disease. What happened when they switched to modern foods tells us something important.
If saturated animal fat causes heart disease, obesity, and diabetes, then populations eating very high levels of it should be the sickest on earth. The opposite has been observed — repeatedly, across different populations, on different continents.
The Tokelau Island Study
The Tokelau Islands in the South Pacific provided one of the most instructive natural experiments in nutrition science. The traditional Tokelauan diet derived approximately 50% of calories from saturated fat, primarily from coconut.
On their traditional diet, Tokelauans had low rates of heart disease, diabetes, and obesity.
When Tokelauans migrated to New Zealand and adopted Western dietary patterns — including refined carbohydrates and seed oils — rates of nearly every metabolic disorder increased significantly (Prior et al., 1981, American Journal of Clinical Nutrition).
The Maasai
The Maasai of East Africa traditionally consumed a diet high in animal fat, meat, and blood — with very high saturated fat intake by Western standards.
A landmark study by Mann et al. (1972, American Journal of Epidemiology) examined Maasai men and found something unexpected: autopsy studies showed evidence of atherosclerosis (fatty deposits in arteries), but virtually no heart attacks. Their coronary arteries had enlarged to compensate — a protective adaptation.
The Maasai example complicates simple narratives in both directions: atherosclerosis was present, but clinical disease was not. Physical activity, caloric intake, and the specific types of fat consumed all likely played roles.
The dietary transition pattern
A 2022 systematic review published in Frontiers in Nutrition examined four traditional populations — Tokelauans, Yemenite Jews, Maasai, and Inuit — to understand what happened when their diets changed.
The findings were consistent: the populations that replaced traditional saturated fats with refined carbohydrates experienced the largest increases in obesity, diabetes, and cardiovascular disease. The two populations with the greatest increases in sugar consumption — Tokelauans (650% increase) and Yemenite Jews (600% increase) — showed the highest increases in diabetes.
The pattern was not "less saturated fat, better health." It was "more processed food, worse health."
The Inuit caveat
The Inuit are often cited in favour of high-fat diets, but their case requires honesty. Research by Fumagalli et al. (2015, Science) identified specific genetic adaptations in Inuit populations — mutations in fat metabolism genes (FADS and CPT1A) — that help them process high-fat marine diets differently from other populations.
This means Inuit metabolic health on a high-fat diet cannot be straightforwardly extrapolated to all humans. Their genetics are part of the story.
What the pattern suggests
Across these diverse populations, a consistent picture emerges:
- Traditional diets high in animal fat — whether from beef, coconut, or marine sources — were not associated with the metabolic diseases we now consider epidemic
- The introduction of refined carbohydrates and industrial foods preceded the rise of obesity, diabetes, and heart disease in every case studied
- The type and processing of food matters more than the macronutrient ratio
This does not prove that seed oils caused metabolic disease, or that tallow prevents it. What it does show is that high saturated fat intake, within a traditional whole-food dietary context, was compatible with metabolic health — and that the transition away from those fats, toward processed foods and refined carbohydrates, was not.
The relevance to tallow
Tallow is a traditional food — the kind of fat that sustained populations for centuries before the metabolic disease epidemic began. Using it as your cooking fat doesn't guarantee good health, but it aligns your diet with the pattern that populations thrived on, rather than the pattern that coincided with the rise of chronic disease.
References: Prior IA et al. (1981) Am J Clin Nutr; Mann GV et al. (1972) Am J Epidemiol; Frontiers in Nutrition (2022) systematic review; Fumagalli M et al. (2015) Science.