Effect of diet and physical exercise on weight, body composition, and resting metabolic rate in obese chilean adults

Resumen

Background: Diet and exercise are the mainstay of weight reduction programs. Aim: To evaluate the effect of diet and exercise on body weight and composition and resting metabolic rate (RMR) in obese adults. Material and methods: Twenty-eight obese adults aged 22 to 61 years (18 women) completed four months of diet and exercise. They attended monthly nutritional consultations, and two-three weekly exercise sessions. At baseline and the end of the intervention, anthropometry, body composition by bioimpedance and RMR by indirect calorimetry (IC) were measured. Metabolic adaptation, defined as a decrease in thermogenesis to an extent greater than predicted based on the change in body weight and composition, was calculated. Results: Significant reductions in body weight and fat mass were observed in both genders. Fat-free mass decreased in women and remained unchanged in men. RMR remained stable. Metabolic adaptation was observed in 11/27 participants. Fat mass change in participants with and without metabolic adaptation was 8 Kg and 4,4 kg, respectively (p = 0,018). In the linear regression analysis, male sex accounted for a higher RMR (247.80 Kcal, p = 0,006) than females. For each kg of fat and fat free mass, the RMR varies 7.25 Kcal, (p = 0.02) and 9.79 Kcal (p = 0,006), respectively. Conclusions: The intervention reduced body weight and fat mass and maintained RMR. Fat free mass decreased in women. Participants with metabolic adaptation showed greater changes in fat mass.