They will have then to enter the laboratory on three different occasions in a randomized order from 8am to 730pm: At 8am they will receive a calibrated breakfast. then, at 1045; they will have to complete one of the experimental condition: 1) one hour of passive video game; 2) one hour of active video game; 3) a cycling exercise. at 1215 and 0630pm, they will be offered ad libitum meals. At regular intervals through the day, their appetite feelings will be assessed using Visual analogue scales.