The authors implement an anthropological approach to explore the evolutionary and cultural explanations of modern obesity. Three widely accepted facts are considered: (1) gender dimorphism (women having higher levels of fat), (2) increase of obesity with modernization, and (3) a positive association between obesity and socioeconomic status. Using theory, cross-cultural research, and case studies, the authors hypothesize how obesity may have been selected for (or not selected against) in an evolutionary context considering both biological and social factors.