Hypothalamic dysfunction at ideal body weight simulating anorexia nervosa.

Hypothalamic dysfunction is common in patients with anorexia nervosa, but typically follows reductions of body weight to well below ideal body weight. We report a patient with hypothalamic dysfunction accompanying volitional weight reduction, whose body weight never fell below ideal body weight and whose hypothalamic function improved following weight gain. These observations suggest that the "set point" for normal hypothalamic function may exceed ideal body weight in some patients. In addition, hypothalamic dysfunction may persist for months following weight gain and the resumption of menses.