The dramatic rise in overweight and obesity during the past several decades can be explained by environmental changes that foster increased energy intake and decreased energy expenditure. There are several reasons to suggest that the most effective approach to weight gain prevention is the incorporate reduced-fat eating into an overall strategy of lowering the energy density of the diet. Our energy density manipulations will be designed to reduce both the fat content and the caloric density of foods served at a cafeteria, which serves as the "food environment" for hospital employees.