Visceral adiposity is associated with increased lipid oxidation in obese, postmenopausal women

Lipolysis is increased in upper-body obese individuals but it is unclear whether body fat distribution is associated with differences in resting metabolic rate (RMR) and/or substrate oxidation in older women. This study determined whether RMR and lipid oxidation are higher in postmenopausal women with visceral obesity. A single-slice computed tomography scan was taken midway between L4 and L5 in 29 women aged 52-72 y with a fat mass of 29.2-68.8 kg. RMR and lipid oxidation rates were measured by using indirect calorimetry. RMR was related to waist circumference (r = 0.45, P < 0.05), but not to waist-hip ratio (WHR; r = 0.23) or intraabdominal fat area (r = 0.26). However, there was a strong, positive relation between lipid oxidation and intraabdominal fat area (r = 0.57, P < 0.01), waist circumference (r = 0.54, P < 0.01), and WHR (r = 0.42, P < 0.05). These correlations remained significant after statistical adjustment for total fat and fat-free mass. These results suggest that in postmenopausal women higher amounts of intraabdominal fat are associated with an enhanced rate of lipid oxidation independent of total adiposity, but not with alterations in RMR.