Research paper
Markwald RR, Melanson EL, Smith MR, Higgins J, Perreault L, Eckel RH, Wright KP Jr. Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain. Proceedings of the National Academy of Sciences. 2013;110(14):5695-5700. doi:10.1073/pnas.1216951110. PMID: 23479616. PMCID: PMC3619301.
Why we cite it
Published in PNAS, this inpatient laboratory study demonstrates the complete energy balance picture of sleep loss — measuring both sides of the equation (expenditure and intake) simultaneously using whole-room calorimetry. The key finding overturns a simple intuition: sleep-deprived people actually burn ~5% more calories (from being awake longer), but they eat far more than the extra burn, primarily through after-dinner snacking. Most strikingly, hormonal signals (leptin up, ghrelin down, peptide YY up) were actively signaling energy surplus — yet participants kept eating. This demonstrates that sleep-loss-driven overeating overrides the body's own satiety signals, making it particularly resistant to willpower-based approaches. Weight gain occurred in just 5 days. The project uses this to explain why sleep is a weight management tool, not a luxury.