How even a couple bad nights shift your hunger hormones toward overeating.
What the evidence says
- Ghrelin (hunger hormone) increases 28% with sleep restriction, in 12 healthy young men given 2 days of sleep restriction ”under controlled conditions of caloric intake and physical activity”. Under free intake, a five-day study found that ”Insufficient sleep led to 0.82 ± 0.47 kg (±SD) weight gain despite changes in hunger and satiety hormones ghrelin and leptin, and peptide YY, which signaled excess energy stores”[1],[2]
- Leptin (satiety hormone) decreases 18% with sleep restriction[1]
- Hunger ratings rose 24% and appetite ratings 23%. The study measured ratings, not eating: caloric intake was controlled by design, and it measured no intake, no expenditure and no weight[1]
- Changes occur within just 2 nights of restricted sleep, in a crossover trial of 12 healthy young men[1]
- The shift is food-specific: appetite for calorie-dense, high-carbohydrate foods rose 33-45%, while appetite for fruits, vegetables and high-protein foods was not significantly affected[1]
- The authors’ own stated limitation: ”The study included only 12 young men and did not measure energy expenditure.” It measured hormones and subjective ratings of hunger and appetite, not intake, expenditure or weight, so it cannot speak to energy balance or to weight gain[1]