Sex and race differences in caloric intake during sleep restriction in healthy adults.
Level 3 - non-randomized controlled study
Non-randomized within-subject laboratory intervention study comparing demographic subgroups without a parallel control group.
PubMed 24965304 · doi:10.3945/ajcn.114.086579
What was done
Forty-four healthy adults aged 21–50 years (mean ± SD: 32.7 ± 8.7 years; 21 women, 16 whites) completed an in-laboratory protocol with 2 baseline nights (10 or 12 h time in bed per night) followed by 5 consecutive sleep-restriction nights (4 h time in bed per night, 0400–0800). Caloric intake, macronutrient consumption, and meal timing were measured across the 2 days after baseline sleep and the first 3 days after sleep restriction to compare differences by sex and race.
What was found
During sleep restriction, subjects significantly increased daily caloric intake (P < 0.001) and fat intake (P = 0.024), consumed more calories from condiments, desserts, and salty snacks (Ps < 0.05), and consumed 532.6 ± 295.6 cal during late-night hours (2200–0359). Men consumed more daily calories at baseline and during sleep restriction, had a greater increase in caloric intake during restriction (d = 0.62), and consumed a higher percentage of daily calories during late-night hours (d = 0.78, Ps < 0.05) compared to women. African Americans and whites did not differ in total daily caloric intake, caloric increase, or meal timing, but African Americans consumed more carbohydrates, less protein, and more caffeine-free soda and juice (Ps < 0.05).
Why it matters
This study demonstrates that acute sleep restriction promotes excess energy intake predominantly via late-night snacking, with men showing greater behavioral susceptibility to increased intake during restricted sleep.
Limits
The study was limited by a small sample size (n = 44), a brief 5-night laboratory intervention that may not reflect real-world sleep habits, and the absence of a parallel non-sleep-restricted control group in the abstract. Energy expenditure, metabolic biomarkers, and long-term body weight changes were not reported.
Cited by
- supports Laboratory sleep deprivation causes subjects to consume an average of 350 to 600 additional calories per 24 hours, predominantly through post-dinner snacking.