Association of Evening Eating with Sleep Quality and Insomnia among Adults in a Brazilian National Survey

Objective To examine the association of evening eating clock time, its elapsed time to the midpoint of sleep (TEM), consumption of caffeine and sugary foods, and dinner meal size with sleep quality indicators and insomnia. Methods The present study's participants ( n = 2,050; 18-65 y) were part of a population-based research, with virtual data collection. Logistic regression models were fitted to assess differences in the odd ratios (ORs) (95% confidence interval [CI]) of sleep duration < 7 hours, sleep latency > 30 min, poor sleep quality, and insomnia (outcomes) with the evening diet-related variables. Linear regression analyses evaluated differences in sleep duration and latency associated with the same variables. Restricted cubic splines were used to investigate the shape of the association of mealtime and TEM with sleep duration and latency. Results For each hour delay in evening eating and increase in the duration of TEM, the odds of sleep duration < 7 h [OR(95%CI):1.30(1.20,1.40); OR(95%CI):0.51(0.47,0.56)], sleep latency > 30 [OR(95%CI):1.14(1.07,1.22); 0.88(0.83,0.94)], poor sleep quality [OR(95%CI):1.21(1.13,1.30); 0.80(0.76,0.85)] and insomnia [OR(95%CI):1.12(1.04,1.20); 0.89(0.84,0.95)], respectively, increased and decreased. We found a dose-response association of evening eating (clock time and TEM) with sleep duration. The shortest latency was seen when evening eating was at similar to 8 PM and similar to 7 to 8 hours before the midpoint of sleep. Participants who reported dinner as their largest meal and consumed caffeine and/or sugary foods/beverages after 6 PM presented higher odds of sleep duration < 7 hours, poor sleep quality, and insomnia. Conclusions Our findings indicate that an early-eating schedule has beneficial sleep effects and that it will be necessary to consider evening eating patterns and timing, along with sleep and circadian hygiene, to improve sleep quality and circadian health.