• Twenty-four-hour measurements of wrist and ankle kinetic energy expenditures were obtained on 20 hospitalized female anorectics during the first two weeks of their hospitalization. Kinetic energy was examined against measures of weight, depression, and Minnesota Multiphasic Personality Inventory scores in a regression analysis. Effect of cyproheptadine hydrochloride, amitriptyline hydrochloride, and placebo on activity was assessed. The results supported previous studies showing a positive relationship between weight gain and motor activity and challenge the commonly held notion that activity decreases in anorectics as their clinical condition improves. Motor activity was initially significantly suppressed by cyproheptadine and subsequently increased.