Effects of aerobic exercise and obesity phenotype on abdominal fat reduction in response to weight loss

OBJECTIVE: To test the effects on abdominal fat reduction of adding aerobic exercise training to a diet program and obesity phenotype in response to weight loss. DESIGN: A prospective clinical trial with a 14-week weight-loss intervention design. SETTING AND PARTICIPANTS: In total, 209 overweight and obese women were assigned to four subgroups depending on type of treatment and the subject's obesity phenotype: diet alone (DA) with intra-abdominal fat (IF) obesity (>= mean IF area), diet plus exercise ( DE) with IF obesity, DA with abdominal subcutaneous fat (ASF) obesity (< mean IF area) and DE with ASF obesity. Abdominal fat areas were evaluated by CT scans, with values adjusted for selected variables. RESULTS: Values were adjusted for age, menopausal status and change in body weight and total fat mass. The IF reductions were significantly (P < 0.0001) greater in subjects with IF obesity phenotype (-45.1cm(2)) compared to the ASF obesity phenotype (-22.2cm(2)). The ASF reductions were significantly (P < 0.001) greater for subjects with ASF obesity (-74.5cm(2)) compared to IF obesity (-55.5cm(2)). For IF obesity, the IF reduction was significantly (P < 0.01) greater in the DE group (-49.3 cm(2)) than in the DA group (-37.8cm(2)). CONCLUSION: These results suggest that for individuals with IF obesity, the efficacy on reducing IF of adding aerobic exercise training to a diet-alone weight-reduction program is more prominent (-49.3 cm(2)/-37.8cm = 1.3 times) compared with DA. Moreover, abdominal fat reduction was found to be modified by obesity phenotype in response to weight loss.