Abstract Introduction Circadian disruption related to misalignment between food-intake timing and endogenous circadian rhythms may contribute to the onset and exacerbation of Inflammatory Bowel Disease (IBD) symptoms. Here, we investigated whether circadian meal timing, regularity, and eating window were associated with intestinal inflammation, clinician-rated disease severity, and self-reported quality of life among patients with IBD. Methods We leveraged baseline data from a randomized clinical trial of adults with active Crohn’s disease or ulcerative colitis (N=39). Participants completed seven days of food-timing logs and wore a Fitbit Charge 5TM to monitor sleep and activity at baseline. Circadian meal timing was calculated as the difference between the timing of each meal and sleep midpoint corrected for the sleep-debt accumulated over the week (MSFsc). Additional exposures of interest included day-to-day variability in meal timing, eating window duration, and breakfast skipping. Outcomes were measured at day 8 following the baseline assessment of sleep and food-timing logs. Outcomes included fecal calprotectin (intestinal inflammation), quality of life assessed by self-reported Short Inflammatory Bowel Disease Questionnaire (SIBDQ), and clinician-rated disease activity (active vs. inactive). We used linear and logistic regression models adjusted for age, sex, IBD type, and disease duration. Results Later circadian timing of the first meal was significantly associated with higher intestinal inflammation (β: 0.427; 95%CI: 0.159, 0.694) in the adjusted model. Similarly, greater day-to-day variability in the circadian timing of the first meal was significantly associated with lower quality of life scores (β: –4.99; 95% CI: –8.59, –1.39). A longer eating window was significantly associated with lower intestinal inflammation (β: -0.244; 95%CI: -0.486, -0.001) and was also associated with better quality of life and lower disease activity, though not statistically significant. Breakfast skipping showed unfavorable but non-significant associations across all outcomes. Conclusion Circadian misaligned eating patterns—particularly a later circadian onset of eating and greater irregularity in meal timing—was associated with higher intestinal inflammation and poorer quality of life in adults with IBD. These findings highlight circadian-aligned eating behaviors as a potential avenue for adjunctive, non-pharmacologic therapeutic strategies in IBD. Support (if any) Supported by R01 DK136520
Su et al. (Fri,) studied this question.