Supervised exercise versus non-supervised exercise for reducing weight in obese adults.

Aim. The prevalence of obesity is rising. Because obesity is positively associated with many health related risks and negatively associated with life expectancy this is a threat to public health. Physical exercise is a well known method to lose fat mass. Due to shame of their appearance, bad general condition and social isolation, starting and continuing physical exercise tends to be problematic for obese adults. A supervised training program could be useful to overcome such negative factors. In this study we hypothesized that offering a supervised exercise program for obese adults would lead to greater benefits in body fat and total body mass reduction than a non-specific oral advice to increase their physical activity. Methods. Thirty-four participants were randomised to a supervised exercise program group (N.=17) and a control group (N.=17). Fifteen candidates in the intervention group and 12 in the control group appeared for baseline measurements and bought an all inclusive sports pass to a health club for €10, per month. The control group just received the oral advice to increase their physical activity at their convenience. The supervised exercise group received biweekly exercise sessions of 2 hours with an estimated energy expenditure of 2 500 kJ per hour. Both groups received no dietary advice. Results. After 4 months the overall decrease in body mass in the intervention group was 8.0 kg (SD 6.2) and the decrease in body fat was 6.2 kg (SD 4.5). The control group lost 2.8 kg overall (SD 4.2) and the decrease in body fat was 1.7 kg (SD 3.1). Correction for differences between groups in gender and age by multiple linear regression analysis showed significantly greater loss of total body mass (P = 0.001) and fat mass (P =0.002) in the intervention group compared with the control group. Conclusion. Stimulation of physical activity alone seems to result in a slight short term body mass and fat mass reduction in obese adults who are eager to lose weight. Supervised exercise under supervision of a qualified fitness instructor leads to a larger decrease.