Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain.
Level 2 - randomized trial
Controlled inpatient experimental trial in humans
PubMed 23479616 · doi:10.1073/pnas.1216951110
What was done
Sixteen adults completed a 14- to 15-day inpatient protocol comparing 5 days of insufficient sleep against adequate and recovery sleep. Researchers quantified total daily energy expenditure, ad libitum energy intake, body weight, appetite hormones (ghrelin, leptin, peptide YY), and circadian melatonin phase.
What was found
Insufficient sleep increased total daily energy expenditure by ~5%, but caloric intake (especially after dinner) exceeded metabolic needs, causing 0.82 ± 0.47 kg of weight gain over 5 days. This overeating occurred despite changes in ghrelin, leptin, and peptide YY signaling excess energy stores. Insufficient sleep delayed circadian melatonin phase. Transitioning to recovery sleep reduced fat and carbohydrate intake and led to -0.03 ± 0.50 kg weight loss.
Why it matters
This study shows that sleep restriction promotes weight gain because behavioral overeating—particularly late-night snacking—substantially outpaces the modest increase in energy expenditure from being awake longer.
Limits
The study was small (n = 16) and short-term (5 days per condition). An inpatient laboratory with unrestricted food access does not necessarily reflect free-living eating behavior, and baseline participant characteristics are not reported in the abstract.