Anorexia and bulimia nervosa are common in western civilized countries. They are among the psychiatric disorders in that they are often accompanied by a variety of life-threatening physical abnormalities. These patients need a close follow-up of the pediatrician in collaboration with the psychiatrist since the changes in bodily functions affect the psychiatric therapy. The challenge to the physician is to use the traditional tools of medicine to diagnose and treat these physical abnormalities using careful medical history, a complete physical examination and appropriate laboratory testing. Peripheral edema is seen as a physical finding in anorexia nervosa (AN) and it is not rare. The estimated frequency is up to 20% among adolescent patients. Peripheral edema in this setting can be easily confused as weight gain. There are five possible mechanisms for its occurrence: hypoproteinemia, electrolyte imbalance, hormonal changes, rapid refeedings, and abuse of laxative, diuretics and diet pills. Patients with eating disorders may ingest a large number of drugs in an attempt to control their weight. We present a case of a female adolescent with AN and peripheral edema who terminated her psychiatric treatment during the refeeding phase because of the unbearable anxiety caused by this edema that affected her body image dramatically. With this case study, we point out the importance of assessing peripheral edema and discriminating it from true weight gain.