Chronic stress is widely known to throw digestion off balance, leading to symptoms like diarrhea or constipation. New findings set to be presented at Digestive Disease Week (DDW) 2026 suggest that eating late at night may make these problems worse, with potential effects on both digestive function and the gut microbiome.
“It’s not just what you eat, but when you eat it,” said Harika Dadigiri, MD, resident physician at New York Medical College at Saint Mary’s and Saint Clare’s Hospital, and the study’s lead author. “And when we’re already under stress, that timing may deliver a ‘double hit’ to gut health.”
Stress and Late Night Eating Linked to Digestive Problems
To explore this connection, researchers examined data from more than 11,000 participants in the National Health and Nutrition Examination Survey. They looked at how chronic stress, late night eating, and bowel issues are related.
Participants with a high allostatic load score, which reflects cumulative physical stress based on body mass index (BMI), cholesterol, and blood pressure, were more likely to report digestive problems. Those who consumed more than 25% of their daily calories after 9 p.m. had a 1.7 times higher risk of experiencing constipation or diarrhea compared to people with lower stress levels who did not eat late.
Gut Microbiome Diversity May Also Be Affected
The pattern held up in another dataset as well. Researchers analyzed information from more than 4,000 people in the American Gut Project and found that individuals with both high stress and late night eating habits were 2.5 times more likely to report bowel issues.
These participants also showed reduced diversity in their gut microbiome. This finding suggests that meal timing could intensify how stress affects gut bacteria through the gut-brain axis, the communication network that links the brain, hormones, nerves, and the microbiome.
Study Highlights Role of Chrononutrition
Because the study was observational, it cannot prove cause and effect. However, it adds to growing evidence around chrononutrition, a field that looks at how the body’s internal clock influences how food is processed.
More research is needed to clarify exactly how stress, eating habits, and gut health interact, but the results point to timing as an important factor.
Small Habits May Support Better Gut Health
Dr. Dadigiri acknowledges that late night snacking is common, especially after long and stressful days, and says she can relate.
“I’m not the ice cream police,” Dr. Dadigiri said. “Everyone should eat their ice cream — maybe preferably earlier in the day. Small, consistent habits, like maintaining a structured meal routine, may help promote more regular eating patterns and support digestive function over time.”
Presentation Details
Dr. Dadigiri will present the findings from the study, “Beyond sleep alone: How stress and late-night eating disrupt bowel habits and gut microbiome diversity, a multi-cohort study,” abstract Mo1769, at 12:30 p.m. CDT, Monday, May 4.