Snacking Before Bed May Increase Liver Disease Risk

Reaching for a snack before bed may seem harmless enough, but new research suggests it could be putting your liver health at risk.

“We know the liver is very much in tune with the body’s circadian rhythms,” says Robert Wilechansky, MD, a study coauthor and a hepatologist at Oregon Health and Science University in Portland. “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.”

Late-Night Eating Was Linked to Higher Liver Disease Risk

Researchers analyzed data from more than 199,000 participants in three long-running U.S. research projects: the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals Follow-up Study. These are some of the longest-running cohort (or group) studies ever undertaken, aimed at tracking how diet and lifestyle affect long-term health and disease risk.

For this study, researchers divided participants into two groups: those who reported late-night eating (after dinner or before bed) and those who didn’t. Then they compared rates of MASLD and cirrhosis between the groups.

Over an average follow-up period of 16 years, about 4,500 participants developed MASLD, and 315 developed cirrhosis. Late-night eaters were 36 percent more likely to develop MASLD, and 28 percent more likely to develop cirrhosis than their peers who didn’t eat later in the evening.

Researchers found that the link between late-night eating and liver disease remained even after accounting for factors such as body mass index (BMI), diabetes, physical activity, alcohol consumption, total calories, and diet quality.

For Bernard Srour, PharmD, PhD, a research professor at the French Institute for Agriculture, Environment, and Food (INRAE) in Paris, the long follow-up period is particularly noteworthy.

“Knowledge is scarce on the long-term associations between meal timing and MASLD,” Dr. Srour says, noting that much of the existing evidence comes from animal studies or short-term clinical trials. Srour was not involved in the new research.

Why Eating Late Might Affect Your Liver

One possible explanation for the findings involves the body’s circadian rhythms, the internal biological clocks that regulate functions such as sleep, digestion, and metabolism throughout the day.

The liver has its own internal clock, which helps coordinate how it processes and stores nutrients. “Meal timing is known to be the main external time-cue for peripheral clocks of the liver,” Srour says.

In other words, eating at a time when the body is biologically preparing for sleep could interfere with those processes.

“We are seeing over and over again that the timing of behaviors, whether it’s sleep, eating, or exercise, really matters,” says Andrew McHill, PhD, a coauthor of the study and an associate professor and sleep and circadian physiologist at Oregon Health and Science University.

McHill says the liver may be particularly vulnerable when eating patterns fall out of sync with the body’s circadian rhythms.

Limitations and Areas of Future Research

Despite its size and lengthy follow-up period, the study was observational, meaning researchers couldn’t determine whether late-night eating directly contributed to liver disease. “Even though we were able to adjust for a number of factors (like diet quality, BMI, diabetes, and physical activity), this type of observational analysis is not able to account for all possible factors that could influence the result,” Wilechansky says. “It also is not able to prove causation, only that there is a correlation or association.”

Another limitation is that researchers couldn’t determine exactly what time participants ate, how much they consumed at night, or how close their meals were to bedtime. Srour says this distinction could make a difference, as eating a small snack after an early dinner may not have the same impact as consuming a large, rich meal shortly before sleep.

In addition, because participants were predominantly white healthcare professionals, the findings may not be generalizable to broader populations.

Should You Avoid Eating Before Bed?

So, how late is too late to eat? Researchers don’t yet have a definitive answer. “While we don’t yet know the exact timing of when to stop eating, and it is very likely person-dependent, we generally think you should stop at least two to four hours before your habitual bedtime,” McHill says.

That recommendation wasn’t tested in the study, though. “It is way too soon to give precise recommendations,” Srour adds. In the meantime, experts say the findings suggest that meal timing deserves more attention — but there's no reason to panic about the occasional late-night snack.

• Eat a balanced diet rich in fruits, vegetables, whole grains, and legumes.

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• Stay physically active.
• Manage diabetes and other metabolic risk factors.
• Limit alcohol and sugary drinks.