Influence of postexercise fasting on hunger and satiety in adults

Research demonstrates that exercise acutely reduces appetite by stimulating the secretion of gut-derived satiety hormones. Currently there is a paucity of research examining the impact of postexercise nutrient intake on appetite regulation. The objective of this study was to examine how postexercise fasting versus feeding impacts the postexercise appetite response. In a randomized crossover intervention, 14 participants (body mass index: 26.9 ± 3.5 kg·m^-2; age: 26.8 ± 6.7 years) received 1 of 2 recovery beverages: (i) water control (FAST) or (ii) sweetened-milk (FED) after completing a 45-min (65%-70% peak oxygen uptake) evening exercise session (∼1900 h). Energy intake was assessed through a fasted ad libitum breakfast meal and 3-day food diaries. Perceived appetite was assessed using visual analogue scales. Appetite-regulating hormones glucagon-like peptide-1 (GLP-1), peptide tyrosine-tyrosine (PYY), and acyl-ghrelin were assessed pre-exercise, 1 h after exercise, and the morning following exercise. FAST increased subjective hunger compared with FED (P < 0.05). PYY and GLP-1 after exercise were decreased and acyl-ghrelin was increased in FAST, with these differences disappearing the day after exercise (P < 0.05). Ad libitum energy intake at breakfast the following morning did not differ between trials. Overall, in the absence of postexercise macronutrient consumption, there was a pronounced increase in objective and subjective appetite after exercise. The orexigenic effects of postexercise fasting, however, were not observed the morning following exercise. Novelty Postexercise fasting leads to reduced GLP-1 and PYY and increased hunger. Reduced GLP-1 and PYY after exercise is blunted by postexercise nutrient intake. Energy intake the day after exercise is not influenced by postexercise fasting.