Adults who eat at inconsistent times are 1.55 times more likely to experience depressive symptoms than those who maintain regular meal schedules, according to a new study. The findings suggest that the timing of meals plays a more direct role in emotional stability than the composition of the diet itself.
A research team led by Professor Tae Hye-jin of the Department of Psychiatry at Seoul St. Mary's Hospital, the Catholic University of Korea (Lifelong Health Promotion Center), published the study in the June 2026 issue of the Journal of Affective Disorders, the medical community said Tuesday. The journal is classified as Q1 in the psychiatry category of the Journal Citation Reports (JCR).
The analysis drew on nine years of data from the Korea Disease Control and Prevention Agency's National Health and Nutrition Examination Survey, covering 2014 to 2022, with a sample of 21,568 Korean adults. The researchers combined Patient Health Questionnaire-9 (PHQ-9) scores with multivariate logistic regression analysis to track the correlation between eating habits and depression. The 1.55-times risk ratio held even after controlling for income, education, smoking, drinking, exercise levels, and underlying conditions. Of the sample, 1,131 individuals, or 5.2 percent of the total, showed clinical depressive symptoms, and this group simultaneously demonstrated higher rates of skipping breakfast and greater variability in meal timing.
A closer look at the variables reveals the mechanism. Among those who consumed all six food groups — grains, vegetables, fruits, meat, legumes and nuts, and dairy — the rise in depression risk associated with irregular meal timing was modest. By contrast, in groups whose diets were concentrated in only one or two food groups, the negative effect of irregularity appeared most steeply. This suggests that dietary diversity may serve as a kind of buffer.
Breakfast deserves separate attention. The link between irregular eating and depressive symptoms was strongest among respondents who frequently skipped breakfast, while those who regularly ate breakfast showed a notably lower risk despite similar irregularity in other meals.
The research team explained this through the hypothesis that breakfast helps establish a baseline for emotional regulation by coordinating circadian metabolic rhythms together with the secretion of serotonin and cortisol. Subgroup analyses showed the same pattern more pronounced among men, smokers, and respondents who habitually ate late-night snacks.
The findings carry added weight when read against the backdrop of Korea's dietary landscape. According to the Korea Disease Control and Prevention Agency's 2022 National Health Statistics, the domestic breakfast-skipping rate stands at 34 percent — twice the level in the United States (16 percent) — and approaches 60 percent among people in their 20s. This means that young adults, for whom skipping meals and late-night eating have become routine, substantially overlap with the high-risk group identified in this study. Previous international research has also repeatedly reported that irregular eating disrupts gut microbiome balance and circadian rhythms, triggering chronic inflammation along the gut-brain axis and contributing to pathways leading to depression.
"This study quantifies, using large-scale population data, what regular meal frequency means for the prevention of depression," Professor Tae Hye-jin said. "The three pillars of regular eating, preventing skipped breakfasts, and diversifying food groups can serve as strategies that are immediately applicable in daily life without pharmaceutical intervention."
Corresponding author Professor Chae Jeong-ho added, "Depression cannot be reduced to a problem of emotion alone and should be viewed as a signal that wavers alongside life rhythms such as sleep, activity, and eating. Correcting eating habits can function as a supporting axis in mental health management."
