Plain language summary
The timing of food intake appears to affect the robustness of circadian rhythms in metabolic organs, and circadian rhythm disruption is emerging as a new risk factor for cardiovascular disease. As major risk factors for cardiovascular diseases, obesity and metabolic syndrome are critical worldwide issues. In Korea, 3 in 10 adults have obesity or the metabolic syndrome. The aim of this study was to explore meal timing and frequency using various variables, including nightly fasting duration and specific time periods such as morning and night, and to examine their associations with obesity and metabolic syndrome in Korean adults using national survey data. The study used data from the 2013–2017 Korea National Health and Nutrition Examination Survey (KNHANES), which is a continuous annual survey conducted by the Korea Centers for Disease Control and Prevention Results indicated that a greater number of eating episodes was associated with lower prevalence of metabolic abnormalities in men. Furthermore, the prevalence of metabolic syndrome was inversely associated with morning eating in both men and women, whereas it was positively associated with night eating in men. Authors conclude that having desirable eating patterns, including eating in the morning and avoiding eating after 21:00, and an appropriate sleep schedule may be helpful for reducing the risks of obesity and metabolic syndrome, independently of fasting duration.
Abstract
Emerging studies indicate that meal timing is linked to cardiometabolic risks by deterioration of circadian rhythms, however limited evidence is available in humans. This large-scale cross-sectional study explored the associations of meal timing and frequency with obesity and metabolic syndrome among Korean adults. Meal timing was defined as nightly fasting duration and morning, evening, and night eating, and meal frequency was estimated as the number of daily eating episodes using a single-day 24-hour dietary recall method. Meal frequency was inversely associated with prevalence of abdominal obesity, elevated blood pressure, and elevated triglycerides in men only. Independent of the nightly fasting duration and eating episodes, morning eating was associated with a lower prevalence of metabolic syndrome (odds ratio (OR), 0.73; 95% confidence interval (CI), 0.57-0.93 for men and OR, 0.69; 95% CI, 0.54-0.89 for women) than no morning eating, whereas night eating was associated with a 48% higher prevalence of metabolic syndrome (OR, 1.48; 95% CI, 1.15-1.90) than no night eating in men only. Longer fasting duration and less sleep were associated with obesity and metabolic syndrome. These findings suggest that overall eating patterns, including energy distribution across the day, eating frequency, and sleep duration, rather than fasting duration alone, are related to cardiometabolic risks in free-living Korean adults.
Methodological quality
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