Does Sleep Affect Weight Gain?

Upon entering college, it’s been hard for me to get my usual 8 hours of sleep. Between studying, sorority meetings, and going out with friends I find that many times sleep falls at the bottom of my priority list. Because of my new habit of staying up late, I find that I tend to eat more since I’m awake for more hours of the day. This hunger then leads me to making some popcorn, eating some ice-cream, or even going as far as ordering Gumby’s famous pokey sticks with my roommate late at night. I’ve started to consider the idea that lack of sleep really does affect your weight gain because of it’s impact on our hunger and decided to look into it further.

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Image foundĀ here.

It is commonly said that a lack of sleep causes weight gain; but why? I found out that insufficient sleep affects our hunger and 2 hormones in our bodies called, ghrelin and leptin that affect our “fullness” sensation. The first hormone, ghrelin is responsible for releasing signals in our brains that says “it’s time to eat”. Insufficient sleep causes the body to produce more ghrelin. The second hormone, leptin is responsible for telling your brain when to stop eating. When you are sleep deprived the body produces less of this hormone and thus, you tend to eat more. Another hormone that is impacted from little sleep is the stress hormone, cortisol. The levels of this hormone spike which tells your body to conserve energy since you are awake for a longer amount of time. This then leads to your body holding on to more fat, causing weight gain (Web MD).

There have been many studies performed that help prove this hypothesis. One was conducted by the Nurses’ Health Study where researchers followed 60,000 women for 16 years recording different aspects of their lifestyles such as weight, sleep habits, and diet. It is important to know that at the beginning of the study, all women involved were healthy with no weight issues. At the end of the study, 16 years later, it was found that women who slept under 5 hours per night had a 15 percent higher risk of becoming obese in contrast with those who slept more than 7 hours per night. Results also showed that women who had insufficient sleep were at a 30 percent higher risk of gaining 30 pounds over the course of the study than those who slept 7 or more hours (Harvard School of Public Health).

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Image foundĀ here.

After many tests and studies, scientists and researchers conclude to reject the null hypothesis that lack of sleep has no negative effects on our health and/ or weight gain. There are several potential mechanisms behind this, one being that insufficient sleep directly causes over eating/ weight gain through the over/ under production of certain hormones in our bodies that control our hunger. Another regarding a third z variable that because people are awake for longer periods of time during the day, they eat more, which then causes weight gain. Another potential possibility could be that perhaps short sleepers are too tired to exercise or perform any physical activity and thus, end up sitting around or laying down more frequently causing weight gain. Further possibilities such as reverse causation, meaning that weight gain/ obesity causes a lack of sleep, are unlikely as I have not found any research that could provide possible causes for that. As always, chance is a possibility and it could be a coincidence that people who get a short amount of sleep tend to gain more weight than those who get 7+ hours.

After researching this topic I decided I should start prioritizing my sleep more if I want to avoid the “freshmen 15”. While I have yet to show any significant weight gain since my late night habits, it is reasonable to conclude that getting insufficient sleep long term can have some negative side effects such as weight gain. Although chance is still a possibility in terms of weight gain, it is still a good idea to get between 7-9 hours of sleep each night. With that being said, sweet dreams!

9 thoughts on “Does Sleep Affect Weight Gain?

  1. Emma Murphy

    Avery, this post was so relatable for me. In high school, I would go to bed by 8 or 9 every night but i college that has changed drastically. I go to bed now around 12 or 1 in the morning. I have noticed that throughout the day I am not hungry, but once it gets to be later at night I find myself munching up until I go to sleep. Although I haven’t personally experienced any significant weight gain yet, your post prompted me to look more into the ways that sleep deprivation could be affecting my body and health. I found this article that gave me more information and tips on how to improve my sleep cycle and avoid weight gain.

  2. Jackson Grey Hope

    These statistics are very compelling, however, I am one of the kids that can prove this study wrong. As you said, there are definitely confounding variables to this study, one being one’s metabolic rate. Someone with a fast metabolism, me being one of them, makes it harder for them to put on weight. I think getting less sleep can actually cause people to lose weight. I am currently pledging a fraternity, and I have been getting on average about 4-5 hours of sleep a night. I have lost about 5-10 pounds since pledging has started, and sometimes if people get less sleep it is because they are more busy and do not even have time to consume the typical three meals they need in a day. Another confounding variable could be exercise. Obviously those who exercise more will prevent themselves from gaining weight. Although the statistics you incorporated provide a correlation, there are definitely confounding variables to this study, and I am living proof that less sleep does not cause weight gain. Also, when people get less sleep and are very busy, they often drink coffee and other stimulants to keep them up so they can get their work done. Coffee for example activates the digestive system causing one to excrete waste more often which can also lead to weight loss. Check out this article from the opposite perspective.

  3. Victor William Gregory

    Hey Avery! I found your blog to very compelling. In retro-spect, it makes a lot of sense. The weeks a get a lot of sleep, I don’t eat much, whereas the weeks I loose sleep, I eat significantly more. The one thing I found to be lacking in this article is the research into the possibility of it being reverse causation. Maybe it is that people who are heavier have less sleep than those who are under weight. This is a link to an article that discusses how obesity can cause a person to loose sleep. I think this topic should be looked into more as it applies to every student on campus.

  4. Chelsea Greenberg

    As someone who is getting much less sleep than they’re used to, I am totally late-night snacking and using order up way too much! You did a good job at incorporating class terminology, such as hypothesis, mechanism, and confounding variable. However, in your fourth paragraph, when you mention the “many studies”, it seems a little unsupported. I would include a hyperlink to other studies besides the ones you explain in your blog to provide more evidence to support your case. Overall, your blog was interesting and thoughtful, and I sure hope that I can get in 8 hours of sleep tonight!

  5. Brandon Ross Armitt

    When you come into college as Freshman, you along with your friends are constantly on the lookout for any signs of the freshman 15. Most people say that this comes from the meals that your eating because they might not be quite the best for you. But one thing that sometimes goes unnoticed and might be just as big of a factor are the late night snacks. When 10 o’clock hits and you aren’t even close to finishing your homework, you are more likely to pull out the bag of chips. The majority of the time you aren’t even hungry, rather just looking for something to keep you occupied. Someone else posted a blog about how Oreos are as addictive as cocaine, which can significantly play a role into weight gain when there is a lack of sleep. At one point your slowly eating the snack, and the next thing you know there is nothing left and you ate triple the serving size. You can see that there is a strong correlation between how focused someone is while studying to how much food the person is going to intake. But its not going to be just freshman who fall victim to this, rather anyone who will be studying late at night.

    This website talks about science behind the reason lack of sleep causes weight gain and ways it can be treated:

  6. Darby Helen Smith

    This blog post is very relatable to me because every since I have gotten here, I have stayed up way later than ever before and the amount of food that I eat in a day has increased. I rarely get to sleep before 3AM when before I would go to sleep at midnight. Within these three hours I gain the hunger for a fourth meal within my day, when usually I would be sleeping. I know that this will soon catch up to me and now after reading this post and seeing that there are real scientific theories that this lack of sleep causes weight gain I will definitely be trying to get to sleep earlier!

  7. Mary M. Brown

    I’ve also noticed a correlation between my decrease in sleep and increase in eating, especially late at night. All day I find myself eating normally, but between the hours of 9pm and 1am, if I’m awake for long enough, I snack beyond belief. This reminded me of our class discussion on the correlation between levels of exercise and eating habits post strenuous exam or study period. As a result, I’ve started going to the gym later at night, between 8pm and 9pm, then coming home to start my work. I’ve actually noticed that I’m less tempted to snack and more satisfied by drinking water, doing my work quickly, showering and going to bed. This article by the Wall Street Journal describes the correlation between lack of sleep and overeating the following day, which I actually never thought about.

  8. Julia R Martini

    Probably everyone in the world could relate to this post at one point in their life. Now, most of the freshman are juggling with this problem but everyone has gone through it at one point. After reading this, I would say that correlation does not equal causation, meaning, not sleeping does not cause weight gain. If a person doesn’t sleep but also don’t eat, they won’t gain weight, but most of the time that isn’t the case. If a person stays up late they usually do eat because it’s longer time to feel hungry. Here’s a little more information on sleeping and eating.

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