Late-Night Eating While Stressed May Disrupt Gut Health, Study Suggests

Eating late at night while experiencing high levels of stress may significantly increase the risk of digestive problems, according to new preliminary research presented at Digestive Disease Week 2026.

Researchers found that people who consumed more than 25% of their daily calories after 9 p.m. while under chronic stress were up to 2.5 times more likely to experience abnormal bowel habits, including constipation and diarrhea.

The findings, which have not yet undergone peer review or been published in a scientific journal, are based on observational data and do not establish a direct cause-and-effect relationship between stress, late-night eating, and gut health.

Lead author Dr. Harika Dadigiri said the study was inspired by her own habit of eating late at night and the limited research available on how meal timing affects digestive health. Previous studies have primarily focused on the relationship between late-night eating and conditions such as obesity, diabetes, sleep disturbances, and acid reflux.

The research team analyzed health information from more than 11,000 participants in the U.S. National Health and Nutrition Examination Survey (NHANES) and over 4,100 participants from the American Gut Project, now known as the Microsetta Initiative.

According to the findings, late-night eating alone did not appear to negatively affect bowel function. However, when combined with chronic physiological stress, the likelihood of digestive disturbances increased substantially.

Researchers also observed that participants who both ate late at night and experienced high stress levels had significantly lower diversity in their gut microbiome. A diverse gut microbiome is generally considered a marker of good digestive health and resilience against disease.

Dr. Geoffrey Preidis of Baylor College of Medicine, who was not involved in the study, noted that stress and late-night eating often occur together, making the findings particularly relevant. He explained that gut microbes play essential roles in nutrient absorption, immune regulation, and communication between the gut and the brain.

Experts cautioned that several potentially important factors were not included in the analysis, such as the types of foods consumed, underlying medical conditions, and medication use. For example, people who eat late at night may be more likely to consume highly processed foods, which have independently been linked to digestive problems.

Although the study does not prove causation, researchers believe that disruptions in the body's natural circadian rhythms may help explain the findings. Both the digestive system and gut microbiome follow daily biological cycles that can be affected by meal timing, stress levels, and dietary habits.

Previous research has shown that limiting food intake to daytime hours may reduce intestinal inflammation and help maintain a healthier balance of gut bacteria. Elevated levels of the stress hormone cortisol have also been associated with disruptions in the gut microbiome.

Gastroenterology experts recommend avoiding food for three to four hours before bedtime whenever possible. This allows the stomach enough time to empty before sleep and may reduce the risk of digestive discomfort and acid reflux.

If a late-night meal is unavoidable, experts advise choosing lighter foods and smaller portions while avoiding heavy, greasy, or high-fat meals. Fruits, vegetables, complex carbohydrates, and lean protein sources are generally easier to digest and less likely to interfere with sleep or digestive function.