This study investigated the acute effects of exercise on the postprandial levels 
of appetite-related hormones and metabolites, energy intake (EI) and subjective 
measures of appetite. Ghrelin, polypeptide YY (PYY), glucagon-like peptide-1 
(GLP-1) and pancreatic polypeptide (PP) were measured in the fasting state and 
postprandially in 12 healthy, normal-weight volunteers (six males and six 
females) using a randomised crossover design. One hour after a standardised 
breakfast, subjects either cycled for 60 min at 65% of their maximal heart rate 
or rested. Subjective appetite was assessed throughout the study using visual 
analogue scales and subsequent EI at a buffet meal was measured at the end (3-h 
post-breakfast and 1-h post-exercise). Exercise significantly increased mean 
PYY, GLP-1 and PP levels, and this effect was maintained during the 
post-exercise period for GLP-1 and PP. No significant effect of exercise was 
observed on postprandial levels of ghrelin. During the exercise period, hunger 
scores were significantly decreased; however, this effect disappeared in the 
post-exercise period. Exercise significantly increased subsequent absolute EI, 
but produced a significant decrease in relative EI after accounting for the 
energy expended during exercise. Hunger scores and PYY, GLP-1 and PP levels 
showed an inverse temporal pattern during the 1-h exercise/control intervention. 
In conclusion, acute exercise, of moderate intensity, temporarily decreased 
hunger sensations and was able to produce a short-term negative energy balance. 
This impact on appetite and subsequent energy homeostasis was not explained by 
changes in postprandial levels of ghrelin; however, 'exercise-induced anorexia' 
may potentially be linked to increased PYY, GLP-1 and PP levels.