Abstract
BACKGROUND: Studies associate sleeping and eating late in the day with poor dietary quality and higher obesity risk but differences in sleep duration confound this association. We aimed to determine whether sleep and meal timing, independent of sleep duration, influenced food intake in healthy adults. METHODS: This was a controlled, 2 × 2 inpatient crossover study with normal (0000-0800 h) or late (0330-1130 h) sleep and normal (1, 5, 11, and 12.5 h after awakening) or late (4.5, 8.5, 14.5, and 16 h after awakening) meals. Food intake was controlled while blood samples were obtained for determination of appetite-regulating hormones on days 3-4. Self-selected food intake was assessed on day 5. Data were analyzed using linear mixed model analysis with sleep, meal, and sleep x meal interaction as dependent variables. RESULTS: Five participants completed all phases (mean age 25.1 ± [SD] 3.9 y, body mass index 29.2 ± 2.7 kg/m(2)). There was a significant sleep x meal interaction on energy intake (P = 0.035) and trends on fat and sodium intakes (P < 0.10). Overnight ghrelin concentrations were higher under normal sleep and meal conditions relative to late (P < 0.005) but lower when both were combined (P < 0.001). Overnight leptin concentrations were higher under normal meal conditions (P = 0.012). There was a significant sleep x meal interaction on ghrelin (P = 0.032) and glucagon-like peptide 1 (P = 0.041) concentrations, but not leptin (P = 0.83), in response to a test meal. CONCLUSIONS: Our results suggest that alignment of sleep and meals may influence food choice and energy balance. Additional research is necessary to expand and confirm our findings.