The exact time you should stop eating for the day has been debated for some time.

Many factors influence when a person stops eating, such as appetite, habits, culture, work schedules, personal preferences, and social settings.

The primary concern for most people is that eating too late may contribute to weight gain. Everyone has an opinion on the best time to stop eating, but you may wonder whether any of it is based on scientific research.

This article examines the best time to stop eating and the health effects of eating late in the day.

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Many people are interested in when they should stop eating at night due to the perception that late-night eating causes weight gain.

It’s well established that eating more than your body needs contributes to weight gain. Thus, if you’re doing a lot of late-night eating on top of your regular meals, you may gain weight (1).

Recently, research has examined the timing of meal intake and its effects on health (1).

This means that it may not only be what you eat but also when you eat that affects your weight and health.

Though there’s no established time when you should stop eating at night, various approaches outlined below may help you find a time that works for you.

Circadian rhythm

The 24-hour body clock, also known as your circadian rhythm, may influence the best time to eat based on its effects on hunger, nutrient absorption, insulin sensitivity, and metabolism (2, 3, 4).

To match your body clock, the recommended eating window is less than or equal to 8–12 hours a day, during daylight hours. Eating outside of this window may lead your body to process calories less efficiently, which may contribute to weight gain (5).

One study found that when mice were fed a high fat meal according to their circadian rhythm, they had significantly lower weights than mice fed the same high fat meal outside of their circadian rhythm (6).

Furthermore, eating over a period greater than 12 hours a day may increase your risk of obesity, diabetes, and heart disease (3).

In a small study including 8 men with prediabetes, eating within a 6-hour window from 8 a.m. to 2 p.m. resulted in improvements in blood sugar levels, blood pressure, and appetite (7).

In another study, fasting blood sugar levels adults in adults with prediabetes were lower when they ate within an 8 a.m.–5 p.m. window than from 12–9 p.m. (8).

This may be why shift workers — whose hours are likely to be irregular — may be at a greater risk of chronic conditions like high cholesterol and diabetes. However, these claims are inconclusive (9, 10, 11, 12, 13).

However, the associated increased risk of chronic disease may be due to a combination of poor quality sleep, irregular eating patterns, and other factors (14).

Intermittent fasting

Intermittent fasting involves eating within a specific window — often 8–12 hours — over any time during the day. Thus, it differs slightly from eating according to your body clock.

Intermittent fasting has been linked to improved levels of blood sugar, cholesterol, body fat, and inflammation (15).

Many intermittent fasting regimens suggest skipping breakfast and having most of your meals later in the day (16, 17, 18).

However, some studies note that eating a bigger breakfast and smaller evening meal may lead to better blood sugar control, decreased body fat, and lower hunger levels (15, 19).

Reducing your eating window to 12 hours or fewer may minimize mindless snacking, thus lowering your overall calorie intake and preventing weight gain (20).

Summary

Research on the best time to stop eating at night is mixed. While some studies use intermittent fasting as a guide for meal timing, others believe that eating in accordance with your body clock is the superior choice.

Eating late at night may affect your weight, disease risk, acid reflux, and food choices. Still, bear in mind that more research is needed in each of these areas.

Weight gain

While many people are concerned that eating too late may contribute to weight gain, research is inconclusive.

One theory that may support this claim is the idea that your body’s ability to burn the food you eat — also called food-induced thermogenesis — differs throughout the day. It’s higher in the morning and lower in the evening (21).

Limiting your food intake late at night may also indirectly lead to a reduction in calorie intake, thus preventing weight gain (21).

Still, more research is needed.

Metabolic syndrome

Numerous studies show that eating late or throughout a wide eating window may increase your risk of metabolic syndrome (5, 21, 22, 23, 24).

Metabolic syndrome is a group of conditions that includes insulin resistance, obesity, high blood pressure, and high cholesterol (25).

One study looked at the metabolic effects of a late dinner (9 p.m.) versus a routine dinner (6 p.m.) in 20 adults. The late dinner resulted in higher blood sugar levels the following morning and a reduced breakdown of dietary fat, compared with the routine dinner (22).

In the long term, this may contribute to obesity.

Reflux

Depending on the size and quality of the meal, eating too late may increase your risk of acid reflux, especially if you go to bed shortly after the meal (26).

Reflux occurs when acid in the stomach begins to irritate the esophageal lining. Long term, it may cause gastroesophageal reflux disease (GERD) (26).

In a study that study compared the effects of a 6 p.m. meal with a 9 p.m. meal in healthy adults, the early dinner was shown to reduce acid reflux symptoms (27).

Poor food choices

Eating later in the day may lead you to overeat or choose easy, quick foods that are likely to be unhealthy, such as chips, candy, or ice cream (28, 29).

Indeed, in a study among104 people with obesity, 45% chose sweets as the snack of choice in the evening and night (29).

Plus, not eating enough throughout the day may lead to overeating at night. One review demonstrated that those who had fewer than the average three meals per day felt less full than those who ate three meals or more (30).

Choosing meals that are less filling may also increase your desire to eat (31).

In a study including 35 men with obesity, those who followed a filling diet high in protein and fiber experienced a reduced desire to eat (32).

Summary

Eating late at night may lead to acid reflux and negatively affect blood sugar management, blood pressure, and weight. This may be due to many factors like poor food choices.

A few basic strategies may help you avoid eating late at night.

  • Enjoy regular meals. Eating regular meals throughout the day — especially ones that are very filling, such as those high in fiber and protein — may reduce your desire to eat late at night (32).
  • Avoid keeping snacks at home. “Out of sight, out of mind” pertains to late-night snacking. The more visible a food is, the likelier you are to eat it. If you’re tempted to snack at night, place snacks where you can’t see them — or avoid keeping them at home (33).
  • Brush your teeth. When you brush your teeth, it’s like telling your body that you’re done eating for the day. Plus, some foods don’t taste good after brushing. Have you tried eating an orange straight afterward? I don’t recommend it (34).
  • Drink herbal tea. Instead of rummaging through the fridge after a long day, try forming new healthy habits that don’t involve eating. One simple idea is to brew a pot of calming chamomile tea (35).
  • Go to sleep early. Staying up late may give you more opportunities to raid the fridge at night. Also, getting insufficient sleep may raise hunger hormone levels, leading you to eat more. Aim for 7–8 hours of sleep each night (36, 37).

Although some research suggests that your body may metabolize food differently during the day versus the night, there’s no scientific consensus on the best time to stop eating.

Some evidence suggests that eating late may negatively influence weight and metabolic risk factors. However, the quality and quantity of your meals are just as important.

The best time to stop eating may depend on your individual preferences, as well as other factors like work, hunger levels, and cultural practices.