Elevated ghrelin predicts food intake during experimental sleep restriction

OBJECTIVE Sleep curtailment has been linked to obesity, but underlying mechanisms remain to be elucidated. This study assessed whether sleep restriction alters 24-h profiles of appetite-regulating hormones ghrelin, leptin, and pancreatic polypeptide during a standardized diet and whether these hormonal alterations predict food intake during ad libitum feeding. METHODS Nineteen healthy, lean men were studied under normal sleep and sleep restriction in a randomized crossover design. Blood samples were collected for 24 h during standardized meals. Subsequently, participants had an ad libitum feeding opportunity (buffet meals and snacks) and caloric intake was measured. RESULTS Ghrelin levels were increased after sleep restriction as compared with normal sleep (P < 0.01). Overall, sleep restriction did not alter leptin or pancreatic polypeptide profiles. Sleep restriction was associated with an increase in total calories from snacks by 328 ± 140 kcal (P = 0.03), primarily from carbohydrates (P = 0.02). The increase in evening ghrelin during sleep restriction was correlated with higher consumption of calories from sweets (r = 0.48, P = 0.04). CONCLUSIONS Sleep restriction as compared with normal sleep significantly increases ghrelin levels. The increase in ghrelin is associated with higher consumption of calories. Elevated ghrelin may be a mechanism by which sleep loss leads to increased food intake and the development of obesity.