Does Eating At Night Cause Weight Gain?

I have not always been a big snacker and would usually just eat breakfast, lunch, and dinner and nothing in between. However, when I came to college it became a different story. I felt myself constantly being hungry and needing a snack to fuel my energy when doing homework. Being that I would be doing much of my studying in the evening, I ate more snacks then. I wanted to know, does eating at night make you gain weight? Maybe this could account for the “freshman 15.” The null hypothesis is that eating at night DOES NOT make you gain weight; the alternative hypothesis is that eating at night DOES make you gain weight. I found several experiments that showed differing results.


A six-month study done by Israel researches searched to find if weight gain was influenced by eating more at night. In order to do this, two groups of people were compared: one group who ate the biggest meal at breakfast and one group who ate the biggest meal at an 8 p.m. or later dinner. Oddly, the study found that the people who ate later at night lost more fat and were more full for the six months of the trial. There were also more changes noticed in their fat loss hormones and they lost 11 % more weight than the group who consumed more calories at breakfast. This was a controlled experiment because the researchers chose which group would eat most at either breakfast or dinner. Another study done in 2012 with 78 obese police officers during a six-month trial period found similar results as the previous study. It found that the officers who ate more carbs at dinner lost more weight than the ones who ate more carbs before dinner. The researchers in both studies would have likely accepted the null hypothesis and either have been correct or had a false negative. Both showed that eating at night does not make you gain weight, but it actually makes you lose weight.

Other studies were done that showed an opposite conclusion and that eating late at night did cause weight gain. In 2013, a study was conducted for 12 weeks with 74 obese and overweight women, all who had a metabolic condition. There were two randomized groups of women: a dinner and a breakfast group. Both groups ate the same amount of calories, just at different times of the day either at dinner or breakfast. At the end of the 12 weeks, the women who lost more weight were the ones who consumed all of the calories at breakfast. When looking at this study, I noticed how there could be some factors that led to this conclusion. If people eat most of their calories at breakfast, they are more likely to burn off calories throughout their day, whereas the dinner eaters would not. Also even though the calorie count for each group was the same, the kind of foods each person was eating could have differed greatly. Therefore, I do not believe that this trial shows that one should or should not eat at night when it comes to weight loss or gain. Another trial done by Northwestern University used mice and found that when the creatures ate at night, they gained more weight. Since this trial was done on animals and not humans, the evidence is not trustworthy enough and is only anecdotal.

Even though all of these studies were conducted successfully with randomized control groups, there is still not enough evidence that one should change their eating patterns. Alan Aragon, a nutritionist says that a person’s body does not hold fat more easily at night than at any other time of the day. Time does not have a clear impact on weight gain. There are many confounding variables when trying to figure out if eating at night causes weight gain such as how much food is being consumed, what is being eaten (quality), if one is exercising daily, and if eating at night is keeping someone awake at night. Eating at night is not necessarily bad to do when the food has nutrition, is consumed in small portions, and the food is low in energy. It can be a problem if someone is eating large portions of food at night on a daily basis and is staying awake at night because of his or her eating habits.

In conclusion, I found that late-night eating does not significantly impact your weight, good or bad. However, each person has different cravings on the type of food they might eat at night which could cause different weight gains. This will continue to be a difficult question to answer, but as long as you’re eating healthy and doing daily exercise, you will not necessarily gain weight if you eat at night. Each person has to look out for what might cause him or her to gain weight. Just be careful how much you’re eating and what you’re eating at night when studying for those mid-terms!



7 thoughts on “Does Eating At Night Cause Weight Gain?

  1. Corbin Kennedy Miller

    This hits close to home, because I enjoy both eating food and sleeping, so it puts me in a sticky situation when I find myself stuck between the two. There was actually a study done and researchers found that there is a link between eating food between eating food before bed and gaining weight. Certain enzymes actually ‘know’ when you should be up and getting food and when you should be asleep, so they do not metabolize the food like they should if it’s too late. This is why you can gain weight if you eat too late when you should be asleep.

  2. Alexis Herrington

    I like how you included multiple links of studies in your blog post to validate the reliability of the initial null and alternative hypothesizes. At the end of this post you came to the conclusion that eating at night doesn’t have a significant on weight gain, which was surprising to me. I thought this study was interesting to share and it further my thinking to wondered what promotes nightly snacking other than the obvious answer than hunger. Here: is a link to a study I found on google scholar that suggests late night eating can be correlated with depression, low self-esteem, lack of daytime hunger, or insufficient weight loss of overweight individuals.

  3. Olivia Frederickson

    This is a really great post especially since midterms is upon us and finals will be just around the corner. Your studies show a really good variance in the type of person being experimented on and the results that are seen. Other confounding variables that could be recognized are sex and age since the police officers may be more common in one certain area of both of these categories. In addition, in the Israel study you should also recognize this was not mentioned. On the contrary, I agree that I especially find myself a lot hungrier when I am studying late at night, and sometimes I may crave something more unhealthy. With your conclusion, I decided to find some healthier options for late night studies. This Q&A was also answered by a professor of nutrition, Dr. Barbara Rolls, from Penn State ironically. She answered the same question you asked and agreed saying weight gain from late night eating is mostly a myth. Back to healthier snacks for late night, she provides that “low-calorie-dense” foods including most produce, soups, etc. are great for feeling more full with less calorie intake.

  4. Mackenzie French

    I am the biggest night snacker ever, it’s bad. College especially has made me become an even bigger one. Since I am up late studying and such I always tend to crave a little something, and it’s usually never anything healthy. I have always wondered if this actually caused weight gain. My mom has always told me to never eat past 9 pm, but of course I never listened. I have always been active, I played soccer and tennis and still continue to workout, so I always told myself “eh, I’ll just burn it off tomorrow!” So I agree, I think it all depends on your lifestyle and amount of exercise you do. Anyways, interesting post!

  5. Griffin Lambert Brooks

    Personally I can’t remember the last time I went to bed without eating a midnight snack. When I eat before I go to bed late at night it makes me sleepy and I end up sleeping like a baby. I could possible be one of the most notorious snackers. My mom would always know when I went tot he kitchen to grab some food because I would always leave a container open or not put the oreos away. Here is an article I found that gives us some reasons why eating before bed is good for you.

  6. Jarrod T Skole

    Awesome post! My parents, especially my dad, have always told me not to snack at night due the fact that you will gain weight that way. As I grew up and started to stay up later I tended to snack more at night, but I never saw an increase in my weight. I was always active as a kid and played two sports all the way through high school, so I believe as long as you work out and exercise, snacking a little at night will not affect your weight. I do mean snacking a little, eating a full meal may show some weight gain effects even with the exercise.

  7. Maura Katherine Maguire

    Great post Alyssa! I have always wondered about this. I find myself always craving a late night dessert and feel so sick right before I go to bed. I never knew if it was myself actually gaining weight or I was just psyching myself out. I have never found my constant snacking affecting my weight too much but I think it really depends on your exercise and daily lifestyle like you said.

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