The effects of weight reduction to ideal body weight on body fat distribution

Obesity is a well-known health risk factor. Several studies have demonstrated that upper-body fat distribution plays a major role in the association between increased adiposity and metabolic disorders. The present study was undertaken to evaluate changes in intraabdominal and subcutaneous fat areas in obese subjects undergoing a weight reduction to their ideal body weight (IBW), as defined by a body mass index (BMI) no greater than 21 or body fat less than 30%, and compare the fat distribution at IBW with that of never-obese control subjects. We studied 33 obese women (151% ± 1% of IBW; BMI, 31.6 ± 2.5 [mean ± SE]) before and after weight loss and a control group of 16 never-obese women (101.0% ± 1.0% of IBW; BMI, 21.2 ± 1.1). Eighteen obese women successfully achieved and stabilized at IBW for at least 2 months. Nonsuccessful obese subjects were significantly younger than reduced-weight subjects, but other physical characteristics were similar. In obese, reduced-obese, and never-obese groups, weight was 85 ± 2.0, 62 ± 1, and 58 ± 1 kg; percent body fat was 41% ± 1%, 24% ± 2%, and 23% ± 1%; intraabdominal fat area was 82 ± 5, 28 ± 3, and 25 ± 4 cm 2; waist subcutaneous fat area was 275 ± 15, 120 ± 9, and 81 ± 7 cm 2; hip subcutaneous fat area was 416 ± 17,204 ± 10, and 195 ± 7 cm 2; and waist to hip ratio (WHR) was 0.84 ± 0.02, 0.77 ± 0.01, and 0.73 ± 0.01, respectively. Our findings indicate that with weight reduction to IBW, intraabdominal and hip subcutaneous fat areas are the same as in individuals who are at IBW, BMI 21.1, and have never been obese. WHR and waist subcutaneous fat area remain significantly increased as compared with those in never-obese controls ( P < .05).