Does Eating before Bedtime Make You Fat?

This is a commonly asked question to which the answer you always hear is a "Yes". The belief of becoming fat for going to bed after eating came into light when researchers found a correlation between individuals snacking late at night and having BMI which categorize them as obese. This belief led to a practice of skipping late night food to prevent weight gain.

Well… Is it true? What does Research Say?

Does one gain weight upon eating late at night or just before bedtime?

One theory states that the metabolism slows down when asleep. With slower metabolism, fewer calories get burnt. It concludes saying that the number of calories burnt from the food eaten last is less and therefore, it leads to calorie surplus going into fat storage. This theory has been disproved in the recent days. Studies have shown that there is no slowing down of the metabolism during sleep. While asleep, your body still functions in many ways, the heart beats to its full potential, the lungs are still working, the brain is still very much active etc. All of these actions take energy. Meaning while we are asleep, we still burn calories.

Another theory states that you will get fat due to late night snacking as there is increased insulin production during the night. Since one action of insulin is deposition of fat from the unused calories, majority of the food being consumed late at night is deposited as fat due to increased levels of insulin at night. It is observed via research that the insulin levels at night is more compared to morning but is the same as that of a mid-day reading. If the insulin levels in the night are the same as that of mid-day where fat deposition is not expected to be more, then the same cannot be expected in the night too. Right?

There's also a suggestion stating that eating carbohydrates at night is linked to weight gain. Carbohydrates are one of the body's main sources of energy. When unused they are stored as glycogen and fat. Glycogen has very limited storage space (The liver and muscles), so when that storage space is full, these carbs are stored in the body as fat. However, the time of the day does not decide how much of consumed carbohydrates is stored as fat and or as glycogen.

The Logic of Weight Gain

Simply put, weight gain depends on calorie intake and calorie expenditure. At the end of the day the amount of weight gain depends on the difference between calories in and calories out. If you eat more calories than you burn, regardless of the time of day you munch on those calories, you gain weight.

Now… What can explain the high BMI in late night snacking individuals as suggested by research?

Well… Although there is a correlation, it is linked to the observed simple fact that snacks that individuals eat at night are usually high in calories such as ice-creams, candies, soft drinks, chips etc., that only increase the calories that go in. Does it come out? And it does, in what way are you working towards burning those extra delicious calories? Now, that is a different story all together.

In conclusion, eating before bedtime does not make you fat, provided the calorie balance is maintained.

·       https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425165/

·       https://greatist.com/health/will-eating-night-make-me-gain-weight