You started going to the gym and picked up running. You cut candy and chocolates out of your diet and started mindfully eating more vegetables and more whole foods. Every day you make sure that you drink enough water. You have been dutifully following this new routine for several months and still you don’t see any results when you step on the scale. You might have forgotten one very important aspect – are you sleeping enough?
Research shows that sleep is as integral to losing weight and maintaining healthy bodyweight as a healthy diet and exercise. Lack of sleep is associated with a dysregulation in appetite-controlling hormones which leads to increased food intake, increased body weight, difficulties in losing weight, and a higher risk for obesity.
Lack of sleep disrupts your appetite-controlling hormones
We can all vividly recall how ravenous we can feel after many hours of not eating and the comforting feeling of being full after a nice meal. These feeling are largely mediated by two hormones in our body that regulate when we eat and when we stop eating: ghrelin and leptin.
Ghrelin is a hunger hormone produced in our stomach that is released into our blood stream after a period of not eating. Ghrelin then travels to our brains hunger controlling center located in hypothalamus and tells us that we are hungry and it is time to get some calories.
Leptin, on the other hand, is a hormone produced mainly by our fat cells that inhibits hunger and appetite and makes us feel satiated. Leptin levels correlate with how much fat tissue we have. The more fat cells, the more leptin is released, and the more hunger is inhibited.
Research shows that sleeping too little leads to an imbalance in levels of leptin and ghrelin and therefore dysregulated appetite. Lack of sleep increases levels of ghrelin, making us hungry, while levels of leptin fall, likely making us even hungrier. For example, a 2004 study on 12 healthy men showed that 2 days of sleep restriction leads to an 18% decrease in leptin, 28% increase in ghrelin levels and is associated with 24% increased hunger, 23% increased appetite, especially for calorie-dense foods with high carbohydrate content.
Also, sleeping too little can give you actual “munchies”. Munchies are the hunger one gets after using cannabis. Such cannabis-induced huger is mediated by molecules called cannabinoids. Interestingly, our body naturally produces a class of cannabinoids that are called endocannabinoids (eCBs). Research shows that levels of eCBs rise sharply after restricted sleep (4.5 hours), which is associated with increases in hunger and appetite in sleep-restricted participants.
Lack of sleep makes your brain crave food
In addition to dysregulation in hunger hormones, lack of sleep shifts your brain activity to a pattern of so-called hedonic or impulsive eating. Research shows that sleep restriction leads to significant changes in the activity of brain regions related to cognitive control and reward.
For example, one study examined brain responses of normal healthy-weight people to different types of food after a good night of sleep and after a night of no sleep at all. Researchers showed pictures of different food items to study participants when they were inside a brain scanner and asked them to evaluate how much they wanted each of the food items.
Researchers found that sleep-deprived brain showed reduced activity in brain regions associated with impulse control and cognitive control of our choices. On the contrary, brain regions associated with reward and excessive appetite became hyperactive. As a result, this specific brain activity profile observed upon sleep deprivation was also associated with a significant increase in the desire for weight-gain promoting high-calorie foods, such as ice-cream rather than broccoli.
Lack of sleep makes you eat more and choose sugary, carb- and fat-rich foods
What do all of these dysregulations in our hunger hormones and brain activity lead to? It doesn’t take a professor to answer – eating more! Research shows that the excess food we consume when underslept amounts to 250-350 extra calories per day, which is around 7 extra kilograms of weight per year!
Several factors contribute to such an increase in daily caloric intake when we are sleep-deprived. First, people who sleep too little tend to eat larger portions. Second, sleep-deprived people have more eating occasions or said simply – snack more. This study showed that sleep-deprived people consumed 42% more calories in snacks compared to a well-rested group!
Lastly, it is not only about how much more we eat when we don’t sleep enough, but also what kind of foods we choose. Underslept people tend to choose sugary snacks, high-carbohydrate foods such as pasta and pizza, and high-fat food, such as burgers and buttery treats.
Dieting when sleep-deprived burns lean muscle and not fat
Worse still, dieting when sleep deprived becomes inefficient. A 2010 study showed that sleeping only 5.5 hours per night for 14 days when undergoing caloric restriction decreases fat loss by 55% while increasing non-fat loss by 60%. This means that when you go on a diet and do not make sure you sleep enough, you might be losing precious lean body mass such as muscle, instead of losing fat tissue.
A healthy and balanced diet as well as sufficient physical activity are well known to be crucial for healthy bodyweight. Getting enough sleep is a third effective and scientifically backed method to help you regulate your appetite and either loose those stubborn kilograms or to maintain a healthy weight.
Greer, S. M., Goldstein, A. N., & Walker, M. P. (2013). The impact of sleep deprivation on food desire in the human brain. Nature communications.
Hanlon, E. C., Tasali, E., Leproult, R., Stuhr, K. L., Doncheck, E., De Wit, H., ... & Van Cauter, E. (2016). Sleep restriction enhances the daily rhythm of circulating levels of endocannabinoid 2-arachidonoylglycerol. Sleep.
Hogenkamp, P. S., Nilsson, E., Nilsson, V. C., Chapman, C. D., Vogel, H., Lundberg, L. S., ... & Schiöth, H. B. (2013). Acute sleep deprivation increases portion size and affects food choice in young men. Psychoneuroendocrinology.
Lin, J., Jiang, Y., Wang, G., Meng, M., Zhu, Q., Mei, H., ... & Jiang, F. (2020). Associations of short sleep duration with appetite‐regulating hormones and adipokines: A systematic review and meta‐analysis. Obesity Reviews.
Markwald, R. R., Melanson, E. L., Smith, M. R., Higgins, J., Perreault, L., Eckel, R. H., & Wright, K. P. (2013). Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain. Proceedings of the National Academy of Sciences.
Nedeltcheva, A. V., Kilkus, J. M., Imperial, J., Schoeller, D. A., & Penev, P. D. (2010). Insufficient sleep undermines dietary efforts to reduce adiposity. Annals of internal medicine.
Papatriantafyllou, E., Efthymiou, D., Zoumbaneas, E., Popescu, C. A., & Vassilopoulou, E. (2022). Sleep Deprivation: Effects on Weight Loss and Weight Loss Maintenance. Nutrients.
Soltanieh, S., Solgi, S., Ansari, M., Santos, H. O., & Abbasi, B. (2021). Effect of sleep duration on dietary intake, desire to eat, measures of food intake and metabolic hormones: a systematic review of clinical trials. Clinical Nutrition ESPEN.
Spiegel, K., Tasali, E., Penev, P., & Cauter, E. V. (2004). Brief communication: sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite. Annals of internal medicine.
Wu, Y., Zhai, L., & Zhang, D. (2014). Sleep duration and obesity among adults: a meta-analysis of prospective studies. Sleep medicine.
Zhu, B., Shi, C., Park, C. G., Zhao, X., & Reutrakul, S. (2019). Effects of sleep restriction on metabolism-related parameters in healthy adults: A comprehensive review and meta-analysis of randomized controlled trials. Sleep medicine reviews.