Sleep and meal timing influence food intake and its hormonal regulation in healthy adults with overweight/obesity.

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/m2). 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.

Pilot study of sleep and meal timing effects, independent of sleep duration and food intake, on insulin sensitivity in healthy individuals.

This pilot study tested the independent and interactive effects of sleep and meal times, under identical sleep duration and feeding conditions, on insulin sensitivity (Si) in overweight adults. Participants underwent a 4-phase randomized crossover inpatient study differing in sleep times: normal (Ns: 0000-0800 hours) or late (Ls: 0330-1130 hours); and in meal times: normal (Nm: 1, 5, 11, and 12.5 hours after awakening) or late (Lm: 4.5, 8.5, 14.5, and 16 hours after awakening). An insulin-modified frequently sampled intravenous glucose tolerance test, at scheduled breakfast time, and a meal tolerance test, at scheduled lunch time, were performed to assess Si after 3 days in each condition. Six participants were enrolled (4 men, 2 women; mean age 25.1±[SD] 3.9 years, body mass index 29.2±2.7 kg/m2); only 1 failed to complete her last study phase. There were no effects of sleep and meal times or sleep × meal time interaction on Si (all P>.35), acute insulin response to intravenous glucose (all P>.20), and disposition index (all P>.60) after adjusting for sex and body mass index. Meal tolerance test glucose and insulin areas under the curve were lower during Nm (glucose P=.11; insulin P=.0088). There were a sleep × meal interaction and an effect of meal times on overnight glucose (P=.0040 and .012, respectively) and insulin (P=.0075 and .067, respectively). Sleep timing, without concomitant sleep restriction, does not adversely affect Si and glucose tolerance, but meal times may be relevant for health. Our results should be confirmed in a larger sample.

Effects of continuous positive airway pressure on energy intake in obstructive sleep apnea: A pilot sham-controlled study.

Obesity is among the leading risk factors for obstructive sleep apnea (OSA). A reciprocal relationship between obesity and OSA has been proposed, which may be due to excessive food intake. We conducted a pilot study to test the effects of continuous positive airway pressure (CPAP) on energy intake (EI) in OSA patients using a sham-controlled crossover design. In-laboratory total daily EI was assessed after 2mo of active and sham CPAP. Four men were enrolled (age±SEM: 51.8±2.1y; body mass index: 31.5±1.5kg/m2). All received active treatment first. Meals (breakfast, lunch, dinner, snack) were served in excess portions at fixed times and additional palatable snacks were freely available throughout the day. Total EI was lower after active (3744±511kcal/d) vs. sham (4030±456kcal/d) CPAP but this difference was not significant (p=0.51) due to variability in the free snack intake. When only fixed eating occasions were considered, daily EI was significantly lower in the active (3105±513kcal/d) vs. sham (3559±420kcal/d) condition (p=0.006). This small pilot and feasibility study is the first to utilize a sham-controlled design to investigate the effects of CPAP treatment on objective measures of EI. Findings suggest that CPAP may cause a reduction in fixed meal intake. In demonstrating feasibility of study methodology, our study also suggests a larger randomized sham-controlled trial be conducted to fully characterize the effects of CPAP treatment on EI and energy balance overall.