Background: Acute partial sleep deprivation increases plasma concentrations of ghrelin and decreases those of leptin.

Objective: The objective was to observe modifications in energy intake and physical activity after acute partial sleep deprivation in healthy men.

Design: Twelve men [age: 22 +/- 3 y; body mass index (in kg/m(2)): 22.30 +/- 1.83] completed a randomized 2-condition crossover study. During the first night of each 48-h session, subjects had either approximately 8 h (from midnight to 0800) or approximately 4 h (from 0200 to 0600) of sleep. All foods consumed subsequently (jam on buttered toast for breakfast, buffet for lunch, and a free menu for dinner) were eaten ad libitum. Physical activity was recorded by an actimeter. Feelings of hunger, perceived pleasantness of the foods, desire to eat some foods, and sensation of sleepiness were also evaluated.

Results: In comparison with the 8-h sleep session, subjects consumed 559 +/- 617 kcal (ie, 22%) more energy on the day after sleep restriction (P < 0.01), and preprandial hunger was higher before breakfast (P < 0.001) and dinner (P < 0.05). No change in the perceived pleasantness of the foods or in the desire to eat the foods was observed. Physical activity from 1215 to 2015 was higher after sleep restriction than after 8 h of sleep (P < 0.01), even though the sensation of sleepiness was more marked (P < 0.01).

Conclusions: One night of reduced sleep subsequently increased food intake and, to a lesser extent, estimated physical activity-related energy expenditure in healthy men. These experimental results, if confirmed by long-term energy balance measurements, suggest that sleep restriction could be a factor that promotes obesity. This trial was registered at clinicaltrials.gov as NCT00986492.