The volunteers of the first group (60) performed a maximal aerobic power test on ergocycle to evaluate their maximum aerobic physical capacity (VO2max), in a hospital laboratory. A measurement of the body composition by biphotonic absorptiometry is also carried out to determine their lean and fat mass. Then, the volunteers stay 26 hours in calorimetric rooms (one evening, one night and a day). The data of indirect calorimetry (O2 consumption and production of CO2), heart rate , actimetry and other parameters are taken into account as from midnight. After one night of sleep, the individuals have to carry out series of state or exercises simulating the daily physical-activities (sleeping, writing 15 min, standing-sitting 5 min, standing 15 min, strolling 15 min, rest 20 min, eating 20 min, household 20 min, stepper 20 min, walking on treadmill at increasing speed 3 km/h, 4 km/h, 5 km/h and 6 km/h during 20 minutes). The volunteers have also to answer questionnaires on their perception of hunger, their emotional state and their visual appreciation of 6 food products at 5 times of the day (before and after the breakfast, before and after the lunch and about 16:30 pm). The rest of the time, their activities are free (watching TV, reading, listening radio …). Measurements finish towards 18:00 and volunteers go home. The meals are balanced in proteins/glucides/lipids and cover energy needs. The menus are established by the dieticians. The meals in calorimetric room are prepared in double weighing to make it possible to calculate the actual quantities.