Sex and race differences in caloric intake during sleep restriction in healthy adults

Abstract

Background: Evidence indicates that men and African Americans may be more susceptible to weight gain resulting from sleep loss than women and whites, respectively. Increased daily caloric intake is a major behavioral mechanism that underlies the relation between sleep loss and weight gain.

Objective: We sought to assess sex and race differences in caloric intake, macronutrient intake, and meal timing during sleep restriction.

Design: Forty-four healthy adults aged 21-50 y (mean ± SD: 32.7 ± 8.7 y; n = 21 women, n = 16 whites) completed an in-laboratory protocol that included 2 consecutive baseline nights [10 or 12 h time in bed (TIB)/night; 2200-0800 or 2200-1000] followed by 5 consecutive sleep-restriction nights (4 h TIB/night; 0400-0800). Caloric intake and meal-timing data were collected during the 2 d after baseline sleep and the first 3 d after sleep restriction.

Results: During sleep restriction, subjects increased daily caloric intake (P < 0.001) and fat intake (P = 0.024), including obtaining more calories from condiments, desserts, and salty snacks (Ps < 0.05) and consumed 532.6 ± 295.6 cal during late-night hours (2200-0359). Relative to women, men consumed more daily calories during baseline and sleep restriction, exhibited a greater increase in caloric intake during sleep restriction (d = 0.62), and consumed a higher percentage of daily calories during late-night hours (d = 0.78, Ps < 0.05). African Americans and whites did not significantly differ in daily caloric intake, increased caloric intake during sleep restriction, or meal timing. However, African Americans consumed more carbohydrates, less protein, and more caffeine-free soda and juice than whites did during the study (Ps < 0.05).

Conclusions: Men may be more susceptible to weight gain during sleep loss than women due to a larger increase in daily caloric intake, particularly during late-night hours. These findings are relevant to the promotion of public health awareness by highlighting nutritional risk factors and modifiable behaviors for weight gain related to sleep-wake timing.

Trial registration: ClinicalTrials.gov NCT02128737 NCT02130791.

© 2014 American Society for Nutrition.

Figures

FIGURE 1.

Mean (±SEM) daily caloric intake during baseline and sleep restriction. Subjects consumed more calories during sleep restriction than baseline (P < 0.001; repeated-measures ANOVA). A: Daily caloric intake showed a significant sex × sleep condition interaction (P = 0.012) and a significant main effect of sex (P = 0.004). Men (n = 23) consumed more calories during baseline (P = 0.038) and sleep restriction (P = 0.003) and exhibited a greater increase in caloric intake during sleep loss (sleep restriction − baseline; P = 0.012, d = 0.92) than did women (n = 21). When differences in baseline caloric intake were controlled for, men also exhibited a greater percentage increase in caloric intake than did women (sleep restriction÷baseline; 28.5% compared with 16.9%; P = 0.045, d = 0.62). B: The race × sleep condition interaction for daily caloric intake was not significant (P = 0.83), and there was no main effect of race (P = 0.53).

FIGURE 2.

Sex differences in meal timing during baseline and sleep restriction. A: Men did not differ from women in the mean (±SEM) percentage of daily caloric intake consumed between 0800 and 1459 or between 1500 and 2159 during baseline (Ps > 0.21). B: During sleep restriction, men consumed a lower percentage of daily calories between 0800 and 1459 (P = 0.046, d = 0.52), a similar percentage of daily calories between 1500 and 2159 (P = 0.68), and a higher percentage of daily calories from 2200 to 0359 (P = 0.008, d = 0.78) than did women.