No Sex Difference in Body Fat in Response to Supervised and Measured Exercise

CAUDWELL, P., C. GIBBONS, M. HOPKINS, N. KING, G. FINLAYSON, and J. BLUNDELL. No Sex Difference in Body Fat in Response to Supervised and Measured Exercise. Med. Sci. Sports Exerc., Vol. 45, No. 2, pp. 351-358, 2013. It is often reported that females lose less body weight than males do in response to exercise. These differences are suggested to be a result of females exhibiting a stronger defense of body fat and a greater compensatory appetite response to exercise than males do. Purpose: This study aimed to compare the effect of a 12-wk supervised exercise program on body weight, body composition, appetite, and energy intake in males and females. Methods: A total of 107 overweight and obese adults (males = 35, premenopausal females = 72, BMI = 31.4 +/- 4.2 kg.m(-2), age = 40.9 +/- 9.2 yr) completed a supervised 12-wk exercise program expending approximately 10.5 MJ.wk(-1) at 70% HRmax. Body composition, energy intake, appetite ratings, RMR, and cardiovascular fitness were measured at weeks 0 and 12. Results: The 12-wk exercise program led to significant reductions in bodymass (males [M] = -3.03 +/- 3.4 kg and females [F]= -2.28 +/- 3.1 kg), fat mass (M = -3.14 +/- 3.7 kg and F = -3.01 +/- 3.0 kg), and percent body fat (M = -2.45% +/- 3.3% and F = -2.45% +/- 2.2%; all P < 0.0001), but there were no sex-based differences (P > 0.05). There were no significant changes in daily energy intake in males or females after the exercise intervention compared with baseline (M = 199.2 +/- 2418.1 kJ and F = -131.6 +/- 1912.0 kJ, P > 0.05). Fasting hunger levels significantly increased after the intervention compared with baseline values (M = 11.0 +/- 21.1 min and F = 14.0 +/- 22.9 mm, P < 0.0001), but there were no differences between males and females (P > 0.05). The exercise also improved satiety responses to an individualized fixed-energy breakfast (P < 0.0001). This was comparable in males and females. Conclusions: Males and premenopausal females did not differ in their response to a 12-wk exercise intervention and achieved similar reductions in body fat. When exercise interventions are supervised and energy expenditure is controlled, there are no sex-based differences in the measured compensatory response to exercise.