The Acute Effect of Exercise on Energy Intake in Overweight Women

The role of exercise on short-term appetite regulation is not known. Furthermore mechanisms mediating this relationship need to be established. Purpose: The purpose of this study was to examine how a single bout of exercise influenced energy intake, subjective feelings of hunger, GLP-1 and acylated ghrelin concentrations compared to an exercise condition. Methods: A total of 19 overweight/obese women (BMI: 32.5 +/- 4.3 kg/m2; age 28.5 +/- 8.3 years) underwent two experimental testing sessions (exercise and rest) which were separated by at least 2 days. For the exercise session, subjects walked on a treadmill at a moderate intensity (70-75% of age-predicted maximal heart rate) until an energy expenditure of 3.0 kcals/kg of body weight was achieved. During the resting condition, subjects rested quietly for a similar length of time. Blood was drawn prior to exercise/rest, immediately post-exercise/rest, 30-minutes post, 60-minutes post, and 120-minutes post-exercise/rest and was analyzed for acylated ghrelin and GLP-1 concentrations. Subjective feelings of hunger were measured using a Likert scale prior to each blood draw. From 1-2 hours post-exercise subjects were provided ad-libitum access to a buffet-style meal and energy intake was calculated based upon food intake during this period. Results: There was no difference in energy intake between conditions (exercise: 551.5 +/- 245.1 vs. rest: 548.7 +/- 286.9 kcals). However, relative energy intake, taking into account the energy cost of exercise, was significantly lower in the exercise condition (197.8 +/- 256.5 kcals) compared to the resting condition (504.3 +/- 290.1 kcals; p<0.001). Exercise did not significantly alter acylated ghrelin, GLP-1, or subjective feelings of hunger from pre-testing to post-testing, nor were differences observed between conditions across the entire experimental testing session (p>0.05). Conclusion: Exercise does not appear to acutely influence energy intake in an overweight/obese population, thus making it a valuable component for managing body weight. Future studies should explore potential physiological or psychological mechanisms to explain why energy intake is not increased following a bout of moderate-intensity exercise in this population