Resting energy expenditure in women: Impact of obesity and body-fat distribution

Abstract

Postabsorptive resting metabolic rate (RMR) and diet-induced thermogenesis (DIT) were repeatedly assessed with an indirect calorimetric ventilated hood system in a group of 32 healthy premenopausal obese women, body fat percentage 46.4 ± 0.9 (mean ± SEM), age 38.5 ± 0.9 years. RMR and DIT were also measured in a group of 10 healthy premenopausal non-obese women, body fat percentage 31.3 ± 1.7, age 37,7 ± 2.4 years. The obese women were subdivided according to the waist-to-hips girth ratio (WHR) into three groups with a different type of body fat distribution: A gluteal-femoral obese group (n = 10), WHR < 0.79; an intermediate obese group (n = 10), 0.79 < WHR < 0.85; and an abdominal obese group (n = 12), WHR > 0.85. No significant differences were observed among the obese groups in age, body weight, body fat mass, and fat-free body mass. Body fat distribution was not associated with differences in DIT, pre- and postprandial respiratory quotients and substrate oxidation rates, but the abdominal obese women had significantly higher RMRs adjusted for age, fat mass, and fat-free body mass (6,075 ± 200 kJ/d) in comparison with the gluteal-femoral obese women (5,502 ± 205 kJ/d) and in comparison with obese women with an intermediate body fat distribution (5,517 ± 193 kJ/d), but not in comparison with a non-obese control group, 6,790 ± 261 kJ/d. It is concluded that within the total group of obese women, the non-abdominal obese can be characterized by relatively reduced resting metabolic rates in comparison with either the abdominal obese or with non-obese women.