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HomeDiets & Weight LossDoes Eating Late at Night Cause Weight Gain? Expert Answers

Does Eating Late at Night Cause Weight Gain? Expert Answers

Many believe that to lose weight, you should not eat after 8 – 9 PM. Is this really accurate? Does eating late at night cause weight gain? Can eating too late at night harm your health?

The answer to the question “Does eating late at night cause weight gain?” is YES, if you consume unhealthy foods and go to sleep immediately afterward. Conversely, if you eat healthy foods 3 hours before bedtime and maintain an active lifestyle, eating late at night may not necessarily harm your health. Continue reading to learn more

Does Eating Late at Night Cause Weight Gain?
Does Eating Late at Night Cause Weight Gain?

1. Does Eating Late at Night Cause Weight Gain?

Whether eating late at night causes weight gain depends on several factors such as how long before bedtime you eat, your daily calorie deficit, and the types of food you consume at night. You can look at the following study involving 9 adults:

Eating Late at Night Cause Weight Gain
Eating Late at Night Cause Weight Gain

Study Subjects and Methods:

Nine healthy-weight adults experienced two different eating conditions, with their sleep time fixed from 11 PM to 9 AM.

  • Daytime Eating Only: Three main meals and two snacks from 8 AM to 7 PM for eight weeks.
  • Including Late-Night Eating: Three main meals and two snacks including a meal at 11 PM for eight weeks.

The subjects had a two-week break to ensure the study conditions. Experts took blood samples at the start and analyzed hormones after the experiment to measure changes in weight, metabolism, and energy.

Study Results:

  • Weight Gain in Late-Night Eaters: Late-night eating resulted in less lipid metabolism and more carbohydrate metabolism. Additionally, negative metabolic profiles, including higher insulin, fasting glucose, cholesterol, and triglycerides, led to weight gain.
  • Daytime Eaters: The hormone ghrelin, which stimulates appetite, peaked earlier in the day, while leptin, which creates a feeling of fullness, peaked later. Therefore, eating earlier in the evening could prevent overeating at night and reduce weight gain risk.

In summary, eating late at night negatively impacts weight, causing higher blood sugar and insulin levels, increasing the risk of diabetes, as well as higher cholesterol and triglycerides, affecting cardiovascular health and other conditions.

2. Eating and Circadian Rhythms

From a circadian rhythm perspective, the answer to “does eating late at night cause weight gain?” is YES. According to the Mayo Clinic, you should avoid eating late at night because it disrupts your body’s insulin sensitivity.

The body is more sensitive in the morning, providing energy for the day. Eating late at night increases insulin resistance, causing excess calories to be stored as fat while you sleep. Over time, this leads to weight gain.

Eating and Circadian Rhythms 
Eating and Circadian Rhythms

3. Late-Night Eating Affects Food Choices

Late-night eaters tend to consume more and choose unhealthier foods. Often, nighttime cravings lead to high-calorie, convenient foods like chips, cookies, and ice cream.

These foods are like dopamine boosters, making us feel better at night, especially for those stressed from work or study. This makes it harder to control calorie intake.

Late-Night Eating Affects Food Choices
Late-Night Eating Affects Food Choices

4. Eating Late After Exercise

What about those who exercise before dinner? According to the U.S. National Library of Medicine, consuming a 150-calorie protein-rich drink 30 minutes before bedtime (after 2.5 hours of exercise) can improve muscle protein synthesis and metabolism for men. However, these effects on healthy women are still unstudied.

Therefore, eating late at night is not entirely bad but depends on the situation. If you maintain a daily calorie deficit by exercising regularly, you can enjoy a light, healthy late-night snack without worrying about weight gain.

Eating Late After Exercise
Eating Late After Exercise

5. How to Eat Late Without Gaining Weight

Although the answer to “does eating late at night cause weight gain” is yes and it’s best to limit late-night eating, there are situations where late-night eating is unavoidable due to work or study demands. Therefore, Grove Health Bondi suggests some healthy ways to eat late to minimize negative health effects.

How to Eat Late Without Gaining Weight
How to Eat Late Without Gaining Weight

5.1 Timing for Late-Night Eating

Ideally, you should eat dinner about 3 hours before bedtime. This allows your body time to digest the food, prevents sleep disruption, and helps those with acid reflux avoid discomfort before sleeping.

Conversely, eating dinner too early and going to bed hungry can also affect sleep and have negative effects. For those who eat dinner early but stay up late, a healthy late-night snack can improve health and sleep quality.

Experts recommend that if you eat dinner early, the last meal should be around 7 PM. If you’re a night owl, the last meal should be at 9 PM. The key is to keep a 3-hour gap between eating and sleeping to ensure better sleep and health.

5.2 Preferred Foods for Late-Night Eating

Grove Health Bondi suggests some healthy late-night snacks:

  • Vegetables, carrots, broccoli with hummus
  • Steamed vegetables or raw veggies like cherry tomatoes
  • An apple with a spoon of peanut butter
  • Some fruit with a small piece of dark chocolate
  • Almonds, walnuts
  • Greek yogurt

These foods provide protein and healthy fats, creating a feeling of fullness and providing moderate energy for nighttime activities.

5.3 Foods to Avoid at Night

Whether eating late at night causes weight gain also depends on the foods you eat. The risk of weight gain and obesity is higher if you consume the following foods before sleeping:

  • High-fat and sugary foods like candy bars, ice cream, fast food, fried chicken, etc.
  • Alcohol: Besides excess calories, alcohol can affect sleep quality.
  • Coffee: Caffeine causes sleeplessness and affects the next day. Additionally, coffee contains sugar, increasing insulin levels, which is unhealthy.

5.4 Exercise Regularly

To avoid worrying about whether eating late at night causes weight gain, it’s best to combine daily exercise to maintain a calorie deficit, preventing excess calories from turning into fat. Despite a busy life with work and study, try to spend at least 20-30 minutes on gym workouts, yoga, running, swimming, or stair climbing for healthy and effective weight loss.

Exercise Regularly
Exercise Regularly

I hope this answers the question does eating late at night cause weight gain?” and helps you understand the various aspects of late-night eating, encouraging healthy eating habits and a positive lifestyle for your well-being.

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Glenn Salkeld
Glenn Salkeld
Professor Glenn Salkeld is a health economist with more than 30 years experience in public health research and a PhD in the economics of preventive health care. Glenn has a particular interest in screening and diagnostic test evaluation based on the implementation of multi-criteria decision analysis.

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