REGIONAL FAT PLACEMENT IN PHYSICALLY FIT MALES AND CHANGES WITH WEIGHT-LOSS

The abdomen is the principal site of fat deposition in men, and becaus e abdominal fat is readily mobilized during exercise, the relative pro portion of fat in the abdominal site may negatively correlate with the amount of regular physical activity, and even with physical fitness. This study presents data for regional fatness in 165 fit young men (U. S. Army Ranger candidates; initial body fat = 14.7 +/- 4.7%) assessed by dual-energy x-ray absorptiometry (DEXA), and for relative changes o ccurring following a 13% weight loss produced by a 1000 kcal . d(-1) e nergy deficit over 8 wk. Fat-free mass was constant across quintiles o f percent body fat; only fat mass was different (16.2 +/- 2.2 kg and 6 .0 +/- 1.4 kg at upper and lower quintiles, respectively). Truncal fat accounted for about 41% of total body fat in all quintiles; only the proportion of fat distributed to the arms was significantly higher in the fattest quintiles of men. Among a group of less intensely trained soldiers with the same average fatness as the highest quintile of Rang er students (20%), relative fat distribution to the trunk approached 5 0% of the total fat. Following weight loss, Ranger students lost half of the fat in all regions assessed (legs, arms, and trunk). The only s ignificant association between regional losses and initial fatness was a greater proportion of fat lost from the arms in the fattest Rangers . These data suggest a ''fit fat'' distribution in active young men in which fat remains in the arms and legs until extreme weight loss occu rs and the metabolically more active abdominal fat approaches depletio n.