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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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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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!