The carnivore connection hypothesis: revisited

Abstract

The "Carnivore Connection" hypothesizes that, during human evolution, a scarcity of dietary carbohydrate in diets with low plant : animal subsistence ratios led to insulin resistance providing a survival and reproductive advantage with selection of genes for insulin resistance. The selection pressure was relaxed at the beginning of the Agricultural Revolution when large quantities of cereals first entered human diets. The "Carnivore Connection" explains the high prevalence of intrinsic insulin resistance and type 2 diabetes in populations that transition rapidly from traditional diets with a low-glycemic load, to high-carbohydrate, high-glycemic index diets that characterize modern diets. Selection pressure has been relaxed longest in European populations, explaining a lower prevalence of insulin resistance and type 2 diabetes, despite recent exposure to famine and food scarcity. Increasing obesity and habitual consumption of high-glycemic-load diets worsens insulin resistance and increases the risk of type 2 diabetes in all populations.

Figure 1

The Carnivore Connection hypothesis [1] and association with recent increased prevalence of insulin resistance (IR) and type 2 diabetes in susceptible (e.g., Pima Indian) and nonsusceptible (e.g., European) populations.

Figure 2

Interaction between modern lifestyle factors such as obesity, physical activity, and changing dietary intake (including energy density, glycemic index, and fiber) and the prevalence of insulin resistance (IR) and type 2 diabetes.