Body fat distribution and energy metabolism in obese men and women

Abstract

Objective: Upper body obesity seems to be associated with a better prognosis for weight loss than does lower body obesity. However, the impact of body fat distribution on energy metabolism is not clear.

Subjects: One hundred fifteen non-diabetic obese Caucasians (64 males and 51 females) and 108 Caucasian lean controls (82 males and 26 females) were studied.

Methods: Body composition was assessed by hydrodensitometry and body fat distribution was estimated by the waist-to-thigh circumference ratio (W/T). Values of 24-hour energy expenditure (24h-EE), basal metabolic rate (BMR), sleeping metabolic rate (SMR) and respiratory quotient (RQ) were measured in a respiration chamber.

Results: BMR, adjusted for differences in fat-free mass, fat mass, age and sex, correlated with W/T in obese males (r = 0.40; p < 0.01), but not in obese females. Obese male subjects with upper body obesity had BMR significantly higher than those with lower body obesity (2189 +/- 268 vs 1974 +/- 141 kcal/day; p < 0.01), independently of differences in fat-free mass, fat mass and age. No correlations were found between W/T and adjusted 24h-EE, SMR or RQ in all examined groups.

Conclusion: These findings indicate that in obese males, upper body obesity is associated with increased metabolic rate, possibly related to higher levels of lipid turnover in visceral fat.