Effect of a medium-term exercise intervention on fat mass is partially compensated for by increased appetite, but not reduced non-exercise physical activity

Exercise-induced weight loss is often less that expected and highly variable between individuals. This implies some degree of compensation in response to the energy deficit generated by the exercise regime. Given that energy intake (EI) and non-exercise physical activity (NEPA) are major determinants of body weight, compensation in either of these could undermine the exercise-induced energy deficit and compromise weight loss. The aim of this study was to examine changes in body composition, appetite, NEPA and SB in response to a 12-week supervised and monitored aerobic exercise intervention in overweight and obese women. Twenty-four women aged 33.1 years (SD = 11.7) with a body mass index (BMI) of 27.9 kg/m2 (SD = 2.7) completed 12-weeks of supervised exercise (500 kcal, 5 times per week). Body weight, waist circumference (WC), body composition, resting metabolic rate (RMR), total daily energy intake (EI) and subjective appetite sensations were measured at baseline (weeks 0) and week 12. Free-living physical activity (PA) and sedentary behaviour (SB) were measure at baseline, week 1 and 10 of the exercise intervention, and at post-intervention. The study procedures and all study materials were reviewed and approved by the National Research Ethics Service Committee Yorkshire & the Humber. There was a significant reduction in body mass (M = 0.83 kg, SD = 1.85), BMI (M = 0.30 kg/m2, SD = 0.66), WC (M = 3.62 cm, SD = 3.85), fat mass (FM; M = 1.50 kg, SD = 2.18) and a significant increase in fat-free-mass (FFM; M = 0.67 kg, SD = 0.98). There was an increase in total [P = .028], ad libitum [P = .030] and snack box EI [P = .048]. This was accompanied by am increase in hunger [P = .016] and a decrease in fullness [P = .040] throughout the day at the end of the exercise intervention compared with baseline. There was no evidence for a compensatory reduction in NEPA [P = .99] and there was a decrease in SB as a result of increased structured exercise [P = .03]. Twelve weeks of supervised aerobic exercise resulted in significant weight (FM) loss. There was a compensatory increase in EI in response to the exercise that was accompanied by an increase in hunger and a decrease in fullness throughout the day. There was no evidence for a compensatory reduction in NEPA and the structured exercise seemed to displace some SB.