A 24-h energy expenditure study on reduced-obese and nonobese women: effect of beta-blockade.

Twenty-four-hour energy expenditure (EE) and substrate oxidation rates were studied in a respiration chamber in 15 reduced-obese (BMI = 24.7) and 8 nonobese (BMI = 20.1) women. Two experiments were performed, one in which beta-blockade was introduced by propranolol and one with placebo. When adjusted for differences in fat-free mass, no difference in 24-h EE was found between the reduced-obese and nonobese groups in placebo experiments. Propranolol reduced 24-h EE by 2.7% in the reduced-obese group whereas no reduction was seen in the nonobese group. A positive correlation was found between fasting glycerol concentration and lipid oxidation. During daytime, lipid oxidation was reduced and carbohydrate oxidation increased by propranolol only in the nonobese subjects. Propranolol reduced fasting glycerol and free fatty acid concentrations in both groups. Beta-blockade seems to have little effect on sedentary 24-h EE but may have a suppressing effect on lipid combustion.