Late-night eating could be quietly harming your liver, according to a large new study that links out-of-hours snacking to two serious liver diseases. Researchers found that people who regularly ate after dinner or after bedtime had a 36 percent higher risk of metabolic dysfunction-associated steatotic liver disease and a 28 percent higher risk of cirrhosis. The analysis of nearly 200,000 adults, published Oct. 9 in the journal Clinical Gastroenterology and Hepatology, is among the first long-term studies to connect late-night eating directly to fatty liver disease.
Late-Night Eating Linked to Liver Disease Over 16 Years
The research was led by Robert Wilechansky, a hepatologist at Oregon Health and Science University who specializes in liver transplantation, in collaboration with colleagues at Massachusetts General Hospital. The team conducted a pooled analysis of participants from three large U.S. long-term studies, the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals Follow-up Study, all of whom were free of liver disease at the start. Participants had a median age of 59 and completed food and lifestyle questionnaires every two to four years. The questionnaires captured details on late-night eating, breakfast habits, and meal frequency.
During a median follow-up of 16 years, the researchers documented 315 cases of cirrhosis and 4,492 cases of MASLD, the current medical term for fatty liver disease tied to metabolic dysfunction. Late-night eating was defined as eating after dinner or after bedtime. In multivariable-adjusted models, the habit was associated with a 28 percent higher risk of cirrhosis and a 36 percent higher risk of MASLD, and the associations held up when the researchers adjusted for factors including age, body weight, physical activity, smoking, alcohol use, and total calories.
The signal grew even stronger in some sensitivity checks. When the analysis adjusted for night shift work, the cirrhosis association rose to 49 percent higher risk, suggesting that disrupted sleep schedules alone do not explain the finding. Imposing a four-year latency period, which helps rule out the possibility that early undiagnosed disease was changing eating habits, left the associations essentially unchanged. Other timing behaviors fared differently: skipping breakfast and irregular meal frequencies were linked to liver disease in age-adjusted models but lost statistical significance after full adjustment.
Late-Night Eating May Disrupt the Liver’s Body Clock
The researchers think the body’s circadian rhythms may explain why late-night eating carries this risk. The liver follows a daily cycle of metabolic activity, and eating at times when the organ is primed for rest may interfere with how it processes fats and sugars. “We know the liver is very much in tune with the body’s circadian rhythms,” Wilechansky said. “So we’re interested in changing the timing of eating in a way that could make a difference in health, without changing the composition of what people eat.”
“A few studies have hinted at this idea, but this is among the first long-term analyses to explicitly draw the connection to fatty liver disease,” he added. Previous research had already tied late-night snacking to heart disease and obesity, but a clear signal connecting meal timing to liver pathology had remained elusive until now.
The public health stakes are considerable. As much as 30 percent of the U.S. population is affected by fatty liver disease, a prevalence that has climbed alongside rising rates of obesity and metabolic syndrome. If late-night eating contributes to that burden, even small changes in meal timing could matter at scale. “The big takeaway here is that confining your calorie intake to several hours before bedtime might be beneficial,” Wilechansky said.
Context matters for interpreting the numbers. Cirrhosis remained uncommon in the study, with only 315 cases among nearly 200,000 participants over the follow-up period, so the absolute risk for any individual late-night snacker stays low. The research is also observational and relied on self-reported diet, which means it can show associations but not prove that late-night eating causes liver disease. Still, for a habit as widespread as the midnight refrigerator raid, the study offers one more reason to keep the evening meal on the earlier side.