The habit of concentrating a large portion of caloric intake late in the day can lead to negative consequences for gut health, especially in individuals facing continuous stress. This finding was presented in April during Digestive Disease Week (DDW) 2026, a relevant international congress in gastroenterology.
The investigation revealed that people who consume more than 25% of their daily calories after 9 PM and maintain high levels of stress have a higher chance of developing intestinal disorders, such as diarrhea or constipation, in addition to having less microbial diversity.
By analyzing data from two extensive US population databases, researchers noted that the combination of a predominantly nighttime diet and stress was linked to up to 2.5 times higher risk of intestinal changes. However, because it is an observational study, the results only indicate a correlation between these elements, without proving that eating late is the direct cause of digestive problems.
This study strengthens the field of chrononutrition, which studies how the timing of meals impacts various aspects of health. The theory suggests that, even without consuming ultra-processed foods, eating late can harm digestive processes and disrupt the circadian rhythm, which is the biological clock responsible for managing functions such as metabolism, hormone production, and digestion.
Gastroenterologist Patrícia Almeida, from Einstein Israelite Hospital, explains that chrononutrition science has shown that the determining factor is not only what is eaten but also the time of ingestion. She adds that metabolic, digestive, and hormonal processes vary throughout the day, causing the same meal to provoke different reactions depending on the time.
Combined interference of stress and nighttime eating
Although there were already indications that stress or meal timing could affect the gut in isolation, the new data suggest a combined effect. According to Almeida, stress affects communication between the gut-brain axis, altering intestinal motility, mucosal permeability, and modifying microbiota composition. When this occurs simultaneously with consuming a significant portion of calories at night, the body shows a reduced capacity for adaptation.
The research also found a decrease in microbiome diversity among the most stressed participants who habitually ate dinner late. Generally, a richer microbiota is associated with better balance of the intestinal ecosystem and more effective defense against potentially harmful microorganisms, in addition to contributing to the production of substances vital for intestinal function. The physician emphasizes that although microbiome diversity is not the only indicator of gut health, it is considered an important parameter.
It is important to note that this does not imply that every meal eaten after 9 PM is harmful. In the context of the study, the concept of late eating was specifically defined as consuming more than 25% of daily calories after this time. Patrícia Almeida clarifies that the focus is on an eating pattern where a considerable slice of daily intake is concentrated during the night, not an occasional late dinner.
The work does not establish rigid guidelines on nighttime eating, as other factors, such as sleep quality, professional routine, physical exercise, and overall dietary pattern, can influence the results. The main conclusion from the Einstein physician is that the combination of chronic stress with predominantly nighttime eating constitutes a scenario less favorable for gut health.