Late-night eating was tied to up to 30% higher liver disease risk in nearly 200,000 people

People who regularly ate after dinner or close to bedtime had a roughly 20% to 30% higher risk of liver disease than people who avoided late eating, according to a team led by Oregon Health & Science University. The analysis covered nearly 200,000 participants in three long-running U.S. health studies, and it looked at both fatty liver disease and cirrhosis, the scarring stage that can follow.

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The finding is an association drawn from self-reported habits, not a demonstration that a midnight snack damages the liver. Even so, it adds to a growing line of research suggesting that when a person eats may matter alongside what is eaten, and it comes with a clinical trial already recruiting to test the idea directly.

The three cohorts behind the 200,000 figure

The paper, titled “Late-Night Eating is Associated with MASLD and Cirrhosis,” appeared in Clinical Gastroenterology and Hepatology in early October. According to the OHSU summary republished by ScienceDaily, the data came from the Nurses’ Health Study, the Nurses’ Health Study II and the Health Professionals Follow-up Study. Participants reported their eating habits, daily routines and other lifestyle factors, and the researchers grouped them by when they usually ate before comparing rates of liver disease.

Late-night eating was defined broadly as eating after dinner or after bedtime, a point the authors acknowledge. News-Medical’s account of the study notes that the definition and the outcomes both rest on self-reported information, which leaves room for error in how people remember and describe their meals. The coverage did not report hazard ratios or confidence intervals, so the 20% to 30% range is the only effect size available in the public summaries.

Fatty liver disease and the circadian clock

The condition at the center of the work is metabolic dysfunction-associated steatotic liver disease, or MASLD, the current name for what was long called nonalcoholic fatty liver disease. The American College of Gastroenterology describes it as a buildup of fat in the liver in people with risk factors such as diabetes, obesity, high blood pressure or high cholesterol who drink little or no alcohol, and puts its prevalence at up to 30% of people. The OHSU summary similarly says fatty liver affects as much as 30% of the U.S. population.

Only a small fraction of people with fatty liver go on to develop serious disease such as cirrhosis, which is part of why a modifiable habit would be of interest to clinicians who see the condition in so many patients. The same ACG page describes cirrhosis as the stage at which liver cells are gradually replaced by scar tissue, with added risks of liver cancer and end-stage liver disease. Robert Wilechansky, the OHSU hepatologist who led the study, said it is among the first long-term analyses to explicitly draw the connection between late eating and fatty liver disease.

Why meal timing may matter to the liver

Andrew McHill, an OHSU associate professor who studies sleep and circadian physiology and co-authored the paper, offered the proposed explanation. He said the timing of behaviors, “whether it’s sleep, eating, or exercise, really matters.” Eating when the body clock is promoting sleep, he explained, can reduce the body’s ability to metabolize food efficiently, which can feed into obesity, diabetes and poor liver health.

Wilechansky made a related point to local reporters. As KOIN reported, he noted that the liver is closely tied to the body’s circadian rhythms, and he suggested that confining calorie intake to the several hours before bedtime might be beneficial. That is a hypothesis about biological timing, and the study did not test it by changing anyone’s meal schedule. The OHSU summary describes the idea the same way: eating during the body’s preparation for sleep may disrupt liver processes tied to circadian rhythms that regulate metabolism and blood sugar, but it stops short of calling that a tested finding.

Limits of an observational design

Several limits apply. The study is observational, so it cannot establish cause and effect, and other factors tied to late eating could explain some of the gap. Habits that travel with late eating could account for part of the difference, and the public summaries do not spell out how fully the authors adjusted for them. A self-reported question about eating after dinner is also a blunt instrument: it cannot separate a light snack from a second dinner, or a person who eats at 8 p.m. from one who eats at 1 a.m. The authors themselves say controlled studies are needed to show whether eating earlier improves liver health.

That test is under way. Wilechansky is involved in an OHSU clinical study that is recruiting participants, tracking meal timing directly rather than relying on recall, and examining whether earlier eating improves outcomes in people with fatty liver disease. The research was funded through an award from the American Association for the Study of Liver Diseases Foundation. Until that trial reports, the 20% to 30% figure is best read as a flag for follow-up, not a prescription.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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