a DASH diet at 67% of their estimated energy needs to maintain weight and asked to eat all foods provided. Food intake will be measured daily. Body weight and hunger and satiety scores will be measured three times a week. Body composition and energy expenditure will be measured before and after the intervention. 24-hour profiles of hormones and other factors that influence central appetite and weight regulation (insulin, leptin, ghrelin, PYY, GLP-1) will be measured before, and on first and last days of the intervention, to compare acute and chronic metabolic effects of the diets. The analysis of primary outcomes will be based on repeated measures and longitudinal models methodology. This study offers a unique opportunity to explore how extreme differences in dietary composition, before and after weight loss, affect components of energy balance and markers of central appetite and weight regulation. These results will be used to design hypothesis-driven studies of the identified mediators of appetite and weight regulation in response to dietary manipulation.