[Sex-specific changes in body composition during weight reduction].

The aim of this study was to ascertain whether overweight men and women of comparable age, body surface area and weight would display any differences in weight loss or changes in body composition while receiving identical calorie intakes. 15 men and 15 women of mean age 46.7 (26-57) years with obesity (body mass index 29-36 kg/m2) were given a reducing diet containing 700 kcal/d for 4 weeks. The two groups were identical in age, body weight and height. The change in body composition was studied by means of ultrasound and nitrogen balance. The women had thicker layers of subcutaneous fat (241 +/- 8 mm) over all parts of the body than the men (137 +/- 10 mm) (summated measurements at 14 points). Among the men body weight fell from 93.1 +/- 2.1 to 83.8 +/- 2.0 kg, but the women declined only from 92.9 +/- 2.0 to 84.7 +/- 1.9 kg. Although men achieved a greater weight loss (13%; P less than 0.001) the decrease in their subcutaneous fat layer was 33% less (to 117 +/- 9 mm) than in the women (211 +/- 8 mm). Cumulative nitrogen balance among the men was 4.7 times more negative than in women (-104 +/- 14 g versus -22 +/- 11 g); this points to accentuated muscle breakdown. More fat was mobilized in the women than in the men, chiefly from the regions of the limbs and hips.