Exercise energy expenditure is not consciously detected due to oro-gastric, not metabolic, basis of hunger sensation

We tested the hypothesis that exercise energy expenditure (EEE) will elicit reflex metabolic compensations but no increases in hunger. Exercise expended 800 kcal once when fasted and at another time in a post-prandial state. During fasting exercise, pre-meal ratings of hunger were unaffected by EEE, but plasma concentrations of ghrelin, growth hormone and free fatty acids were higher than in the absence of EEE. We propose that the perception of hunger is based on the vagal, lateral hypothalamic and cortical projections of oral and gastro-intestinal (GI) stimuli and that EEE triggers neuroendocrine compensations and influences hunger indirectly by affecting GI functions.