Evidence that shortened period of sleep could be a risk factor for weight gain and obesity has grown over the past decade. Concurrent with the obesity epidemic, numerous studies have reported a parallel epidemic of chronic sleep deprivation. Sleep is important in maintaining energy balance (i.e. acute sleep deprivation impact the normal secretion of ghrelin and decreases leptin plasma levels). Surprisingly, in humans, there is no direct evidence that a shortened night has direct effect on energy metabolism during the following day.

This study is set up to determine whether a partial sleep deprivation night has an impact on appetite and food energy intake and, concomitantly, on physical activity, during the following day.

Inclusion Criteria:

• male
• age between 18 and 30
• healthy
• non smoker
• less than 5 hour of sport per week
• BMI between 20 and 25 kg/m/m

Exclusion Criteria:

• eating disorders,
• dieting or fasting
• restrained (score >9), disinhibited (score >11) or hungry subjects (score >9), according to the Three-Factor Eating Questionnaire general healthiness,
• food-snacking (more than twice a day),

Healthy normal subjects