Nutrition is a relatively new field; yet for thousands of years, humans with no knowledge of the existence of a protein, fatty acid or vitamin have been able to utilize their local dietary resources to construct viable diets. Today, however, with ample nutritional information widely available, most human populations do not appear to be eating properly with the result that many chronic diseases afflicting both modern and developing nations are attributed to dietary factors. Monkeys and apes are the closest living relatives of modern humans and human ancestors presumably ate many foods similar to those consumed by wild primates. Nutritional analysis of some wild foods routinely consumed by free-ranging primates provides a framework for critical appraisal of similar nutritional components in the diet of modern humans. These comparative data suggest that many domesticated plant foods humans consume may differ from their wild counterparts more than is generally appreciated. Bringing nutritional components of the moderm human diet more in line with those of extant monkeys and apes could serve to lower the incidence of some diet-associated diseases.