Your late-night snack could be hurting your liver

If after-dinner snacking is part of your nightly routine, it may be worth reconsidering the habit.

According to a study published Oct. 10 in the journal Clinical Gastroenterology and Hepatology, late-night eaters may have an increased risk of developing fatty liver disease and cirrhosis.

The new research is among the first long-term studies to connect nighttime eating to liver disease. And the reason appears to go beyond excess calories.

Fatty liver? Here’s what to eat and what to avoid

The findings suggest when you eat also plays a role in liver health.

Here’s what to know about the latest research, why occasional nighttime snacking isn’t cause for concern, plus some suggestions for healthier evening snacks.

About fatty liver disease, cirrhosis

Metabolic dysfunction-associated steatotic liver disease, commonly referred to as fatty liver disease, occurs when fat builds up in liver cells.

Metabolic risk factors such as obesity, elevated blood fats, high blood pressure, insulin resistance and Type 2 diabetes increase the likelihood of developing MASLD.

Over time, liver damage can lead to cirrhosis – advanced scarring of the liver that can impair its ability to function normally. It’s estimated that 3 to 5 per cent of people with MASLD go on to develop cirrhosis.

The latest research

For the study, researchers looked at whether what time people eat is associated with the development of MASLD and cirrhosis.

To do so, they analyzed data from 199,155 adults who participated in one of three large long-term U.S. studies: the Nurses’ Health Study, Nurses’ Health Study II and the Health Professionals Follow-Up Study.

Participants, free of liver disease at the start of the studies, were followed for an average of 16 years. Participants periodically reported the times at which they typically ate. Late-night eating was defined as eating between dinner and bedtime or after bedtime.

Late-night snacking linked to greater risk of liver disease

Over the follow-up period, 315 participants developed cirrhosis and 4,492 developed MASLD.

Compared with participants who avoided eating late, late-night eaters had a 28 per cent increased risk of developing cirrhosis and a 36 per cent greater risk of developing MASLD.

To arrive at these findings, the researchers accounted for many factors that could influence liver disease risk, including age, body mass index, calorie intake, overall diet quality, smoking, physical activity, alcohol intake, abnormal blood lipid levels and diabetes.

The association between late-night eating and liver disease persisted even after researchers controlled for night-shift work, which can affect both eating patterns and cardiometabolic health.

Study strengths, caveats

The study’s strengths include its large sample size of nearly 200,000 participants, long follow-up period and repeated measurements of diet and lifestyle factors.

However, while its observational design found associations, it does not prove that late-night eating directly causes MASLD or cirrhosis. As well, late-night eating was broadly defined, so the study couldn’t determine whether eating later at night is associated with greater risk.

Even so, previous research has tied nighttime eating to a greater risk of weight gain, obesity, elevated blood sugar, high blood cholesterol and hypertension – conditions associated with an increased risk of fatty liver disease.

How late-night eating may harm liver health

The liver’s circadian rhythms – its internal 24-hour cycle – help regulate how it processes nutrients, manages blood glucose and stores and uses energy. It’s thought that nighttime eating may disrupt these rhythms.

Research also suggests that eating late in the day may reduce insulin sensitivity, as well as the amount of calories the body burns.

Rethinking nighttime eating

When you eat may matter, but what and how much you eat, as well as other lifestyle habits, remain key to preventing fatty liver disease.

Guidelines recommend maintaining a healthy weight, following a healthy dietary pattern, being physically active and managing metabolic risk factors such as obesity and Type 2 diabetes.

If you’re an occasional nighttime snacker, there’s no need to worry. This study looked at habitual eating patterns.

If you regularly snack because you feel hungry after dinner, consider whether you’re eating enough earlier in the day. To help curb evening hunger, include foods rich in protein and fibre at breakfast and lunch and as part of an afternoon snack.

If you do need an evening snack, choose one that’s minimally processed and nutrient dense, such as a small handful of nuts, apple slices with peanut butter or unsweetened yogurt with berries. Avoid sugary and refined-starchy snacks.

If nighttime snacking is driven by habit rather than hunger, try replacing the snack with a hot unsweetened beverage, such as chai-flavoured black tea, green tea, herbal tea or low-sodium chicken or vegetable broth.

Finally, if work, family or cultural routines mean you regularly eat dinner late, the new findings aren’t a reason to skip your evening meal. When possible, though, consider shifting more of your food intake to earlier in the day and keeping your late-evening meal smaller.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan.