A late-night snack may do more than add extra calories to your day. Researchers analysing data from nearly 200,000 people found that eating after dinner or around bedtime was associated with a higher risk of developing liver disease, including fatty liver disease and cirrhosis.
The findings, reported by Oregon Health & Science University (OHSU) and published in Clinical Gastroenterology and Hepatology, add to growing evidence that when people eat may matter alongside what and how much they consume.The study examined data from 199,155 participants enrolled in three large US health research programmes: the Nurses’ Health Study, the Nurses’ Health Study II and the Health Professionals Follow-up Study. Researchers tracked participants over a median period of 16 years and examined how their eating patterns related to the development of liver disease.The analysis found that people who reported eating late at night had a higher risk of metabolic dysfunction-associated steatotic liver disease (MASLD) and cirrhosis than those who did not report the habit. The adjusted risk was about 36% higher for MASLD and 28% higher for cirrhosis, according to the published findings. These figures represent relative increases in risk, not an equivalent increase in every individual’s absolute likelihood of developing the conditions.
What is MASLD and why does it matter?
MASLD, previously widely known as non-alcoholic fatty liver disease, occurs when excess fat accumulates in the liver in association with metabolic risk factors. These may include obesity, type 2 diabetes and other metabolic abnormalities. Many people with the condition have few or no noticeable symptoms, but some can develop inflammation, liver scarring and more serious complications over time.Cirrhosis is an advanced form of liver damage in which healthy liver tissue is replaced by scar tissue.
It can interfere with the organ’s ability to function and may lead to complications, including liver failure. Not everyone with fatty liver disease progresses to cirrhosis, and the risk varies according to several factors.The researchers set out to investigate whether meal timing was associated with these conditions, building on previous research linking late-night eating with obesity and cardiovascular problems.
The study’s large sample and long follow-up period allowed the team to examine eating habits in relation to liver health over many years.
Why could eating late affect the liver?
One possible explanation lies in the body’s circadian rhythm, the internal 24-hour clock that helps regulate sleep, hormone release, metabolism and other biological functions. The liver plays a central role in processing nutrients, managing blood sugar and regulating how the body stores and uses energy.
Its activity changes according to the body’s daily rhythms. Eating when the body is preparing for sleep could potentially affect how efficiently it processes glucose and fats.Researchers have also studied the health effects of working night shifts, when people’s sleep-wake schedules and eating patterns may conflict with their natural biological rhythms. Such disruptions have been associated with metabolic problems, prompting scientists to investigate whether the timing of food intake could be one contributing factor.However, the precise mechanisms behind the association remain uncertain. The study does not establish that late-night eating directly damages the liver, nor does it show that changing meal times alone will prevent liver disease.
What the study could not establish
The findings are based on an observational analysis of existing health data. Participants reported their eating habits, and researchers compared those reports with subsequent liver disease outcomes.
This approach can identify associations but cannot prove cause and effect.Late-night eating may also be linked to other behaviours or circumstances that influence health, including sleep schedules, work patterns, overall calorie intake and lifestyle. Although researchers adjusted their analysis for several potential confounding factors, such adjustments cannot eliminate every possible source of bias.The study also did not establish that all late-night foods carry the same risk. A snack’s nutritional content, portion size and its place in a person’s overall diet remain relevant questions. Nor does the research identify a single cut-off time after which eating becomes harmful for everyone.The findings should therefore not be interpreted as evidence that an occasional late dinner or snack will cause liver disease.
They point instead to a possible relationship between habitual eating patterns and long-term liver health that warrants further investigation.
Could eating earlier help?
The researchers are pursuing further work to determine whether changing meal timing can produce measurable health benefits. An OHSU team is recruiting participants for a clinical study that will examine eating schedules more directly and assess whether shifting food intake earlier can improve indicators of underlying fatty liver disease.If future trials confirm the association, meal timing could become another factor considered in strategies to support metabolic and liver health. For now, the evidence does not justify treating an earlier dinner as a guaranteed preventive measure.The study adds to a broader area of research often called chrononutrition, which examines how the timing of meals interacts with the body’s biological clock. It suggests that dietary advice may eventually need to consider not only food quality and quantity but also eating patterns across the day.For people concerned about liver health, the findings are a reason to pay attention to habitual routines rather than panic over an occasional late-night snack. The researchers’ central question remains open: whether consistently finishing meals earlier can meaningfully reduce the risk of liver disease.Disclaimer: The study identifies an association and does not prove that late-night eating causes liver disease. People should seek individual medical advice for concerns about liver health.