The chemical ecology of human ingestive behaviors

Ingested nutrients and nonnutrients are presented as determinants in human evolution. The amount and quality of energy, including fat, various foods s upply are important criteria in governing selection. Oxidative stress assoc iated with respiration of energy is a factor in the etiology of dietary dis eases, such as cardiovascular disease and cancer, and in aging. Evolutionar y trends such as gains in brain and body sizes, greater ingestion of long-c hain polyunsaturated fatty acids and cholesterol, heating of fatty food, an d greater longevity increased oxidative stress while greater reliance on an imals foods and less on plants decreased ingestion of exogenous antioxidant s. The hypothesis that selection for nonnutrient ingestive behaviors was a compensatory mechanism for increasing antioxidants is presented within the context of a four-factor model on the origins of human medicine.