Comparing measured dietary variation within and between tropical hunter-gatherer groups to the Paleo Diet

An energetic framework for gut microbiome-mediated obesity induced by early-life exposure to antibiotics

Early-life antibiotic (ELA) exposure has garnered attention for its potential role in modulating obesity risk, although outcomes from mouse experiments and human epidemiological studies often vary based on dosage and sex. Low-dose (subtherapeutic) antibiotics can enhance energy availability through moderate alterations in gut microbiome profile, while high-dose (therapeutic) antibiotics substantially deplete the gut microbiota, thereby contributing to short-term negative energy balance. In this perspective, we propose a framework to understand how these distinct impacts of antibiotics on the gut microbiome during critical developmental windows shape long-term obesity risk through their influence on host energy balance. Using this framework, we then propose several hypotheses to explain variation in ELA-induced obesity outcomes across males and females. We conclude by discussing the evolutionary implications of ELAs, positing that the response of the gut microbiome to ELAs may signal energy availability and environmental volatility, influencing metabolic programming and adaptive traits across generations.

Reverse-engineering the Venus figurines: An eco-life-course hypothesis for the aetiology of obesity in the Palaeolithic

Evolutionary perspectives on obesity have been dominated by genetic frameworks, but plastic responses are also central to its aetiology. While often considered a relatively modern phenomenon, obesity was recorded during the Palaeolithic through small statuettes of the female form (Venus figurines). Even if the phenotype was rare, these statuettes indicate that some women achieved large body sizes during the last glacial maximum, a period of nutritional stress. To explore this paradox, we develop an eco-life-course conceptual framework that integrates the effects of dietary transitions with intergenerational biological mechanisms. We assume that Palaeolithic populations exposed to glaciations had high lean mass and high dietary protein requirements. We draw on the protein leverage hypothesis, which posits that low-protein diets drive overconsumption of energy to satisfy protein needs. We review evidence for an increasing contribution of plant foods to diets as the last glacial maximum occurred, assumed to reduce dietary protein content. We consider physiological mechanisms through which maternal overweight impacts the obesity susceptibility of the offspring during pregnancy. Integrating this evidence, we suggest that the last glacial maximum decreased dietary protein content and drove protein leverage, increasing body weight in a process that amplified across generations. Through the interaction of these mechanisms with environmental change, obesity could have developed among women with susceptible genotypes, reflecting broader trade-offs between linear growth and adiposity and shifts in the population distribution of weight. Our approach may stimulate bioarchaeologists and paleoanthropologists to examine paleo-obesity in greater detail and to draw upon the tenets of human biology to interpret evidence.

Adipose development is consistent across hunter-gatherers and diverges from western references

Despite agreement that humans have evolved to be unusually fat primates, adipose patterning among hunter-gatherers has received little empirical consideration. Here we consider the development of adiposity among four contemporary groups of hunter-gatherers, the Aka, Savanna Pumé, Ju'/Hoansi and Agta using multi-level generalized additive mixed modelling to characterize the growth of tricep skinfolds from early childhood through adolescence. In contrast to references, hunter-gatherers show several consistent patterns: (i) children are lean with little fat accumulation; (ii) no adiposity rebound at 5 years is evident; (iii) girls on average have built 90% of their body size, and reach menarche when adiposity is at its maximum velocity; and (iv) a metabolic trade-off is evident in young, but not older children, such that both boys and girls prioritize skeletal growth during middle childhood, a trade-off that diminishes during adolescence when height velocity increases in pace with fat accumulation. Consistent results across hunter-gatherers living in diverse environments suggest that these patterns reflect a general forager pattern of development. The findings provide a valuable baseline for adipose development not apparent from reference populations. We emphasize both generalized trends among hunter-gatherers, and that inter-populational differences point to the plasticity with which humans organize growth and development.

Unraveling the Evolutionary Diet Mismatch and Its Contribution to the Deterioration of Body Composition

Over the millennia, patterns of food consumption have changed; however, foods were always whole foods. Ultra-processed foods (UPFs) have been a very recent development and have become the primary food source for many people. The purpose of this review is to propose the hypothesis that, forsaking the evolutionary dietary environment, and its complex milieu of compounds resulting in an extensive metabolome, contributes to chronic disease in modern humans. This evolutionary metabolome may have contributed to the success of early hominins. This hypothesis is based on the following assumptions: (1) whole foods promote health, (2) essential nutrients cannot explain all the benefits of whole foods, (3) UPFs are much lower in phytonutrients and other compounds compared to whole foods, and (4) evolutionary diets contributed to a more diverse metabolome. Evidence will be presented to support this hypothesis. Nutrition is a matter of systems biology, and investigating the evolutionary metabolome, as compared to the metabolome of modern humans, will help elucidate the hidden connections between diet and health. The effect of the diet on the metabolome may also help shape future dietary guidelines, and help define healthy foods.