The main objective of the present study was to evaluate the short-term effects of exercise of different intensities on energy intake. Eleven young men were submitted to three randomly assigned sessions (one control and two exercise sessions) in which they ate, ad libitum, foods from a buffet-type meal.The energy cost of exercise was the same in the two exercise sessions. Results showed that there was no significant change in post-exercise subjective levels of hunger and fullness as well as total energy and macronutrient intakes in comparison with the control session. However, when energy intake relative to expenditure was considered by subtracting the surplus of energy expended during exercise from total energy intake, high-intensity exercise exerted a greater reducing effect on this variable compared with the control and low-intensity exercise sessions. These d t s suggest that for a given level of energy expenditure, high-intensity exercise favours negative energy balance to a greater extent than low-intensity exercise. Appetite: Energy expenditure: Physical activity: HungerThe ability of exercise to induce a negative energy balance depends on its impact on energy expenditure and is also related to variations in post-exercise energy intake. Indeed, a highfat diet has been shown to induce a considerable increase in post-exercise energy intake (Tremblay et al. 1994a;King & Blundell, 1995). This effect of diet composition on energy intake also emphasizes the importance of taking into account the potential effect of exercise on food preferences and relative macronutrient intake. In several studies, exercise has been shown to induce a substantial increase in carbohydrate intake (Thompson et al. 1988; Verger et al. 1992) whereas an increase in post-exercise protein intake was found in another study (Verger et al. 1994). However, other investigators did not find a significant effect of exercise on macronutrient intake (King et al. 1994).Experimental evidence suggests that post-exercise energy intake is also influenced by the composition of the substrate mix oxidized during exercise. Indeed, Alm6ras et al.(1 995) observed that high-fat oxidizers during exercise displayed a lower post-exercise energy intake adjusted for the energy cost of exercise compared with individuals expending less energy as fat during exercise. This observation is concordant with our previous finding that exercise may attenuate the impact of a high-fat diet on energy intake depending on its enhancing effect on fat oxidation (Tremblay et al. 1989).Other studies have also investigated the effects of exercise on energy intake and feeding behaviour. In human subjects, most of the reported studies have shown that exercise does not significantly modify appetite or the subjective feelings of hunger and fullness (Reger et al. 1986;Reger & Allison, 1987;Thompson et al. 1988;Kissileff et al. 1990). On the other hand, Kissileff et al. (1990) found that energy intake was lower only after strenuous exercise in lean female subjects. King et al. (1994) have...