Changes in body composition and fat distribution after short-term weight gain in patients with anorexia nervosa.

The most commonly described psychologic abnormality associated with anorexia nervosa is a distorted perception of body weight and shape. This perception may contribute to the anorexic patient's resistance to gaining weight even when it is a medical necessity. The purpose of this study was to assess body-composition and fat-distribution changes after short-term weight gain in 26 female anorexia nervosa patients 27.6 +/- 6.6 (mean +/- SD) y of age, with a body mass index (BMI; in kg/m2) of 16.5 +/- 1.9. They participated in a refeeding protocol both as inpatients (n = 21) and as outpatients (n = 5) until they achieved maximum weight gain. Body-composition and fat-distribution changes were measured by using dual-energy X-ray absorptiometry (DXA) and skinfold thickness and circumference measurements. A mean weight gain of 6.7 +/- 5.3 kg (P < 0.001) was observed, which included significant increases in body fat (P < 0.001), lean body mass (P < 0.05), and bone mineral content (P < 0.01), with body fat being the component that increased the most. When measured by DXA, fat gain was not significantly different among the three central regions: subscapular, 1.7 +/- 1.2 kg; waist, 1.8 +/- 1.3 kg; and thigh, 1.5 +/- 1.0 kg (P = 0.10). Thus, although fat was the largest component of the weight gained, there was no preferential fat deposition in any one area and the female gynoid body shape was maintained.