Environmental context is a core aspect in the shaping of diet and dietary behavior in animals, including humans, but the linkages between habitat variation and prioritization of particular macronutrients in diet is not well understood. This lack of knowledge regarding how habitat shapes macronutrient management behavior is characteristic of modern dietary behavior, as well as from an evolutionary perspective. In humans, evidence has been found for protein prioritization, whereby individuals allow fluctuation of other nutrients around a fixed protein level. Termed 'protein leverage,' this pattern of nutrient balancing has been implicated as a causal factor in the modern obesity epidemic, whereby humans will over-consume energy to meet their protein needs. This aspect of human dietary behavior is hypothesized to have arisen from human evolutionary history in the context of a savanna environment, one in which available foods are proportionally high in protein, but limited in fats and carbohydrates. In order to fully understand how habitat and seasonality may have influenced diet priorities in human ancestry which persist in the modern context, this dissertation project will utilize a primate model, wild baboons, which, like humans, are known for their omnivorous diet and their ecological and dietary flexibility. By comparing these primates across varying habitats and seasonal fluctuations in available food items with variant macronutrient composition, the research will assess how diet may be shaped by environmental context, including how habitat may have shaped human dietary priorities over evolutionary timescales.
The modeling of how differences in habitat shape diet and nutritional priorities will be based on comparative data on the nutritional priorities of female Papio anubis in two different habitats, a forest in Uganda and a savanna environment in Kenya. The research will be conducted by a female doctoral student, Caley Johnson, under the supervision of Dr. Jessica Rothman, City University of New York. Individual nutritional intake data will be assessed in the context of seasonal shifts in the availability and abundance of food, and will employ the Geometric Framework of Nutrition (GF). The GF is a multidimensional analytical approach which has application to research investigating nutritional ecology, including determination of dietary prioritization of nutrients and balancing of macronutrients across species and within species occupying variant habitats. The fieldwork will encompass 12 months of data collection in Kibale National Park, Uganda, and 6 months in Laikipia, Kenya, across wet and dry seasons.
In addition to elucidating the environmental conditions that shape diet and nutrient priorities in omnivorous primates such as humans, this project also will broaden its impact in various directions. The data will find additional value added in pairing with stable isotope data collected for the same areas; this will improve interpretation of stable isotope paleodietary analysis of East African fossil hominins and papionins (early human and baboon ancestors). The enhancement of understanding of baboon ecology in forested environments will generate a unique synthesis of nutrition, ecology, and primate behavior that will promote insights into intraspecific variation in behavior and ecology. As the research is international in scope, there will be fostering of scientific collaborations of US universities and students with African universities and institutions, promoting education and enhancing research capacity.
