Late night eating and sleep habits damage gut health, increase metabolic disease risk

A new study led by UTHealth Houston identified a link between late-night eating and sleeping habits, gut health, and metabolic disease, offering new insights into why some individuals with obesity may face risk of inflammation and related health problems. 

The findings were published in iScience and led by Faraz Bishehsari, MD, PhD, professor and director of the Gastroenterology Research Center in the Department of Internal Medicine at McGovern Medical School at UTHealth Houston. 

Researchers analyzed how circadian behaviors, including sleep and meal timing, relate to metabolic health in adults with obesity. They found that adults with obesity who tend to stay up later and eat later in the day were significantly more likely to exhibit traits associated with metabolic syndrome. Metabolic syndrome is defined as a group of conditions that increase the risk of heart disease, stroke, and Type 2 diabetes. The findings suggest that a mismatch between the body’s internal clock and daily behaviors may contribute to disease risk through changes in the gut microbiome and the intestinal barrier. 

We have long recognized the importance of what we eat for metabolic health, but we are increasingly learning that when we eat may also matter. What makes this study interesting is that it connects circadian behaviors with the gut microbiome, intestinal barrier function, and systemic inflammation.

We wanted to take these findings beyond the clinical setting and examine how eating patterns and their relationship to sleep affect people in their everyday lives.” 

Faraz Bishehsari, MD, PhD, professor and director of the Gastroenterology Research Center, Department of Internal Medicine, McGovern Medical School, UTHealth Houston

Investigators analyzed two aspects of circadian behavior from adults with obesity: chronotype, which reflects whether someone naturally prefers to wake up early or stay up late, and the timing of food intake. Participants with a later chronotype, often described as “night owls,” were more likely to have a higher number of metabolic syndrome risk factors compared to those with an early chronotype, or “early bird.” The greatest metabolic risk was observed among individuals who combined a late chronotype with late-night eating habits. 

Because the gut plays an important role in digestion and overall health, researchers further examined its implications through the creation of a “Metabolic-Inflammatory Score” to understand how the body responds to immune and metabolic changes. Their findings suggest that individuals with higher metabolic risk showed signs of “leaky gut,” which allows substances that are normally kept inside the intestines to enter the bloodstream. When this happens, those substances can trigger inflammation and affect other parts of the body. 

“We know that what we eat matters for our health, but our findings suggest that when we eat is also important. One intriguing possibility is that the gut microbiome and intestinal barrier help explain how disruptions in our daily biological rhythms are connected to metabolic inflammation,” Bishehsari said. 

Researchers also explored whether improving the gut microbiome could help strengthen the intestinal barrier. Participants who demonstrated improvements in gut barrier function following a microbiome-targeted intervention showed an increase in beneficial short-chain fatty acid-producing bacteria. The findings suggest that the microbiome may represent a modifiable pathway connecting circadian behaviors and metabolic health. 

The findings reflect how late sleep schedules and late-night eating contribute to changes in the gut microbiome, weakening the intestinal barrier and promoting inflammation associated with metabolic disease. 

“Because meal timing and other circadian behaviors are potentially modifiable, understanding these relationships could open new opportunities for preventing or managing metabolic diseases through lifestyle changes and interventions targeting the gut microbiome,” Bishehsari said.  

As modern lifestyles increasingly challenge natural sleep and eating rhythms, the findings highlight the potential importance of considering not only diet quality but also meal timing and sleep habits when addressing obesity and metabolic disease risk. 

“Future research will help determine whether therapies aimed at improving circadian alignment or strengthening the gut microbiome can reduce inflammation and lower the risk of metabolic disease,” Bishehsari said. 

Bishehsari is the Atilla Ertan, MD, Chair in Gastroenterology Research at McGovern Medical School, as well as a faculty member at The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences. 

Other UTHealth Houston researchers on the study are Xiangsheng Huang, PhD; Connor Cheek, PhD; and Mahboobeh Mahdavinia, MD, PhD. Additional authors include Edena Khoshaba, MD; Ankur Naqib, PhD; Maliha Shaikh, MS; and Ali Keshavarzian, MD, with Rush University Medical Center, as well as Mohamed Abdel-Mohsen, PhD, with Northwestern University, and Heather Rasmussen, PhD, with University of Nebraska.