Weight loss induced by endurance exercise is often disappointing, possibly due to an increase in energy intake mediated through greater appetite. The aim of this study was to evaluate fasting, postprandial, and postexercise appetite regulation after an intervention prescribing two amounts of endurance exercise. Sixty-four sedentary, overweight, healthy young men were randomized to control (CON), moderate-dose (MOD: ≈ 30 min/day), or high-dose (HIGH: ≈ 60 min/day) endurance exercise for 12 wk. Along with subjective appetite ratings, plasma ghrelin, glucagon, insulin, peptide YY3-36, glucose, free fatty acids, and glycerol were measured during fasting and in relation to a breakfast meal and an acute bout of exercise, both at baseline and at follow-up. Ad libitum lunch energy intake was evaluated 3 h after the breakfast meal. Despite different amounts of endurance exercise, the subjects lost similar amounts of fat mass (MOD: 4.2 ± 0.5 kg; HIGH: 3.7 ± 0.5 kg). Fasting and postprandial insulin decreased ≈ 20% in both exercise groups (P < 0.03 vs. CON). Appetite measurements were not upregulated in the fasting and postprandial states. On the contrary, fasting and postprandial ratings of fullness and postprandial PYY3-36 increased in HIGH (P < 0.001 vs. CON). Ad libitum lunch energy intake remained unchanged over the course of the intervention. In both exercise groups, plasma ghrelin increased in relation to acute exercise after training. Thus neither moderate nor high doses of daily endurance exercise increased fasting and postprandial measures of appetite, but a high dose of exercise was associated with an increase in fasting and meal-related ratings of fullness and satiety.
Keywords: appetite regulation; exercise; food intake; overweight.