The goal of this research is to examine habitual energy expenditure and metabolic responses to dietary and exercise pertubations in black and white female adults with and without an immediate family history of obesity, with the purpose of identifying factors which may contribute to the racial differences in the prevalence of obesity. The studies are designed to address the question of optimal fat intake in black women and fits well with our long-term goal of better understanding the causes of obesity in this high risk minority group and developing dietary and exercise interventions targeted at its successful prevention.