Patients with anorexia nervosa require refeeding to restore normal body weight. A variety of studies have examined the role of metabolic rate in the refeeding of anorectic patients. Several measurement techniques have been used to divide metabolic rate into its components: basal metabolic rate, resting energy expenditure, activity-induced thermogenesis, and dietary-induced thermogenesis. In anorexia nervosa patients several consistent findings are present. First, the number of kilocalories required for weight gain or weight maintenance increases as weight increases. Second, over 50% of the body mass gained in anorectic individuals represents fat tissue. Finally, both a history of bulimic symptoms and a higher premorbid body weight may lead to lower calorie requirements. These findings suggest the need for gradual increase in calories provided throughout treatment; resting energy expenditures may aid the determination of caloric requirements