Sex differences in energy homeostatis following a diet relatively high in protein exchanged with carbohydrate, assessed in a respiration chamber in humans

Context: Obesity prevalence is generally higher in women than in men, and a paucity of research with sex-specific approaches exists. The question arises whether current weight loss programmes, largely developed and tested on women, are appropriate for men. Objective: Investigate 24 h energy metabolism, satiety and related hormones during a diet relatively high in protein (HP), exchanged with carbohydrate compared to an adequate-protein (AP) diet, in a respiration chamber in men, in comparison with previous outcomes in women. Design: Ten healthy males (BMI: 22.5 +/- 1.6 kg/m(2), age: 25 +/- 3.5 y) were fed in energy balance with an AP (10/60/30% of energy of protein/carbohydrate/fat) or a HP (30/40/30% of energy of protein/carbohydrate/fat) diet in a randomized cross-over design. Results: During the HP diet, 24 h Energy Expenditure (10.5 +/- 0.5 vs 10.0 +/- 0.5 MJ/d; p<0.05), Sleeping Energy Expenditure (7.1 +/- 0.3 vs 6.9 +/- 0.2 MJ/d; p<0.05), protein balance (0.5 +/- 0.02 vs 0.0 +/- 0.01 MJ/d; p<0.05), satiety (AUC) p<0.05, and plasma GLP-1 concentrations (42 +/- 23 vs 28 +/- 16 AUC; p<0.005) were significantly higher and 24 h RQ (0.80 vs 0.85; p<0.01), fat balance (-0.85 +/- 0.03 vs 0.05 vs 0.03 MJ/d; p<0.01) and hunger (AUC) p<0.05, were significantly lower. Comparisons reveal a stronger reaction in men in energy expenditure and substrate oxidation, whereas satiety reacted stronger in the women. Conclusions: Effects of a diet relatively high in protein exchanged with carbohydrate, vs an adequate protein diet are a stronger increased energy expenditure, fat oxidation, protein anabolism in men, and a stronger increased satiety in women, thereby creating sex-specific conditions for long-term use for body-weight management. (C) 2009 Elsevier Inc. All rights reserved.