Later energy intake within a shorter eating window is associated with adverse metabolic profiles among Korean adults.

BACKGROUND: Mistimed eating has been implicated in adverse metabolic outcomes, including obesity and metabolic syndrome. However, existing studies have largely examined isolated aspects of time-related eating behaviors. OBJECTIVE: This study aimed to identify distinct time-related eating patterns using a data-driven approach and to examine their associations with obesity and metabolic syndrome among Korean adults. METHODS: Data from 16,973 adults aged ≥19 years participating in the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2021 were analyzed. Time-related eating patterns were derived using k-means cluster analysis on four dietary timing variables: morning energy proportion, evening energy proportion, number of eating occasions, and eating window. Multivariable-adjusted logistic regression models were used to assess associations between identified eating patterns and obesity, metabolic syndrome, and their individual components. RESULTS: Three distinct time-related eating patterns were identified: "early," "late-short," and "grazing." Compared with the "early" pattern, the "late-short" pattern was associated with higher odds of metabolic syndrome (odds ratio [OR] = 1.28, 95% confidence interval [CI] 1.11-1.48), elevated blood pressure (OR = 1.23, 95% CI 1.07-1.40), triglycerides (OR = 1.24, 95% CI 1.10-1.40), and fasting blood glucose levels (OR = 1.24, 95% CI 1.11-1.40). The "grazing" pattern was associated with higher odds of elevated fasting blood glucose (OR = 1.24, 95% CI 1.11-1.39), and lower odds of obesity (OR = 0.81, 95% CI 0.73-0.89) and abdominal obesity (OR = 0.82, 95% CI 0.75-0.91) relative to the "early" pattern. CONCLUSION: Distinct time-related eating patterns were associated with metabolic health in Korean adults. These findings highlight the potential relevance of the timing of daily energy intake to metabolic health, with earlier rather than later energy intake being associated with more favorable metabolic profiles. However, longitudinal and interventional studies are needed before implications for prevention can be established.