Caloric requirements for weight gain in anorexia nervosa.

The caloric requirements for weight gain were studied in 29 patients during 35 days of treatment for anorexia nervosa. Associations between the caloric requirements for weight gain and the amount of body weight depletion at the beginning of treatment were analyzed. There was a positive correlation between the percentage standard weight on the 1st day of treatment and the excess calories required to gain a kilogram. This highly significant correlation was possibly due to differences in type to tissue formed and/or an increase in metabolic rate as part of an adaptive response, as the patient nears target weight.