In the last decade or so, sleep researchers have identified associations between short sleep duration and both being overweight and weight gain over time.1, 2, 3 Numerous studies from a range of diverse populations have found that individuals who regularly receive sufficient restorative sleep have healthier weights than those who do not sleep enough. What are some of the reasons underlying these associations? In this blog post, I explore a few of the mechanisms through which we achieve these findings.
If you are sleep deprived, your hunger and fullness hormones change.
Experimental studies have shown that when people are sleep deprived, the hormones that regulate your stomach’s sense of fullness, known as satiety, change.4, 5 Specifically, when sleep deprived, you have a decrease in the hormones that make you feel full (leptin), and an increase in the hormones that make you feel hungry (ghrelin). Even though you probably need about the same number of calories the day after a short sleep, your body is instructing you to eat more!
If you are not getting enough sleep, your dietary choices change.
Research shows that people who do not get enough sleep at night choose to eat foods that are higher in carbohydrates and calories, compared to those who get enough sleep.5, 6 This may not be a surprise to you. I mean, if you have ever found yourself running to the kitchen in the middle of the night, you probably aren’t in the mood to grab the carrots and celery, are you? No; instead, the middle of the night is a perfect time to sneak that last piece of your daughter’s chocolate birthday cake. A related point here is that when you are sleep deprived, you likely have less self-control, and may not be able to resist tasty temptations like potato chips and that bag of gummy bears that somehow appeared in your pantry last month.
Being overweight or obese itself could also lead to poor quality or insufficient sleep.
As with all associational studies, we need to keep in mind that correlation does not mean causation. Indeed, just because sleep deprivation and obesity are associated doesn’t mean that sleep deprivation causes obesity. In fact, the association between sleep duration and obesity may go in the other direction: obesity causes trouble falling asleep or staying asleep.
Finally, there may be lifestyle differences between people who get poor sleep, and these lifestyle differences make them more likely to be overweight.
Perhaps the reason that short sleep duration is associated with obesity has nothing to do with one causing the other. Instead, there may be something about the lifestyles or occupations of short sleepers that cause weight gain. For example, people who spend a lot of time sitting at work (or on the couch at home) may also be more likely to have trouble sleeping, so they are also more likely to be overweight. Similarly, people who regularly eat heavy meals late at night may also have more trouble sleeping. Thus, it is not the obesity itself that is causing insufficient sleep, but rather a third factor (e.g. a sedentary lifestyle or late eating) that is leading to both short sleep and obesity.
So what does this mean for you?
As I’ve outlined in this post, there are a lot of possible reasons why people who get sufficient restorative sleep have healthier weights than those who do not. I’m unable to definitively say whether getting more sleep will help you lose weight; however, given all the benefits of sleep for other health, well-being, and cognitive functioning, I hope you are convinced that getting a good night’s sleep should be one of your priorities for healthy living. You may just find that making more time for sleep also helps your pants fit more comfortably!
Brondel, L., Romer, M.A., Nougues, P.M., et al. (2010). Acute partial sleep deprivation increases food intake in healthy men. American Journal of Clinical Nutrition, 91(6), 1550-9.
Chen, X., Beydoun, M.A., Wang, Y., (2008). Is sleep duration associated with childhood obesity? A systematic review and metanalysis. Obesity, 16, 265–74.
Magee L, and Hale L. (2012). Longitudinal associations between sleep duration and subsequent weight gain: A systematic review.” Sleep Medicine Reviews, 16(3), 231-41.
Patel, S.R., Hu, F.B., (2008). Short sleep duration and weight gain: a systematic review. Obesity, 16(3), 643-53.
Shlisky, J. D., Hartman, T.J., Kris-Etherton, P.M., et al. Partial Sleep Deprivation and Energy Balance in Adults: An Emerging Issue for Consideration by Dietetics Practitioners. Journal of the Academy of Nutrition and Dietetics, 112:11, 1785-97
Spiegel, K., Tasali, E., Penev, P., et al. (2004). Brief communication: sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite. Ann Intern Med, 141:11, 846-50.