The Secret Role of Sleep in Boosting Metabolism

Sleep is something we all know we need more of. We constantly feel tired, but somehow can’t find a way to get to bed any earlier. Unfortunately, getting the full hours of sleep we need each night just isn’t a priority — but it should be. There is a crucial connection between sleep and all of the reactions that take place in our bodies, making a solid night’s rest the key to unlocking a revved-up metabolism.

Why isn’t this common knowledge?

When an individual sets out to take control of their health, many will start by focusing on their diet and implementing movement into their daily routine. While these are both extremely important in reaching your health goals, it takes time and energy to make purposeful changes in your life. Meal prepping, workout classes, and cooking more from home leaves us feeling exhausted and forces us to carve even more time out of already busy lives. Naturally, we give up our precious hours of sleep in order to get these things done. The pounds may still come off, but you can speed up the process by prioritizing your sleep.

How does sleep boost my metabolism?

Sleep is much more than simply laying in bed, it’s a period of time during which our bodies undergo a series of intricate functions that significantly impact our health. Our brains sort through information from the previous day while other cells are repaired and reorganized. Sleep is a very dynamic process – while all of that is going on, hormones and proteins are being released that control our hunger cues and blood sugar levels.

Sleep and hunger

Our brains regulate neurotransmitters — the chemical messengers that carry signals from our brains to our bodies —  when we are sleeping. Although many people assume their empty stomach is the primary reason they feel hungry, two neurotransmitters are actually responsible for the feeling. While ghrelin instigates feelings of hunger, leptin tells our bodies we feel full. The levels of these neurotransmitters change throughout the day, and without sleep, they may become dysregulated. 

In a study of hundreds of men, those who were allowed to get a full night’s sleep had proper levels of these chemicals in their bodies while those who were only allowed to sleep for 4 hours had increased amounts of ghrelin and decreased leptin.

Over time, your sense of hunger and fullness will be extremely thrown off. You may tend to eat more than you need, forcing your body to metabolize food differently and store excess as fat.

Sleep and Energy Conservation

Another reason why your lack of sleep is preventing you from reaching your health goals is that sleep has a profound effect on how our body chooses to break down food. When we are sleep deprived, we induce a stress response in our bodies, causing a spike in the levels of cortisol, a stress hormone. Because of this, our bodies go into saving mode, attempting to conserve energy for the long waking hours ahead.

What does this mean exactly? Your body will convert more of the food you eat into fat, rather than into a usable energy source.

Sleep and Blood Sugar Regulation

When we are sleep deprived, our ability to process insulin decreases drastically. According to a recent study conducted at the University of Chicago, insulin sensitivity dropped by 30% for the group of individuals who got less sleep. When we are sleep deprived, the excess sugar found in our bloodstream will be stored as fat rather than being taken up by cells to be used as energy. 

In our fast-paced lives, work obligations, fitness routines, and social connections are prioritized while sleep tends to take a backseat. Watching our diets diligently and squeezing in workouts can only do so much without sleep supporting these efforts. Although an extra hour of sleep is not going to get you to lose ten pounds overnight, sufficient sleep will set you up for success by putting your body in the ideal position to accomplish your health goals. Sleep truly is the unsung hero that accelerates our progress in becoming our healthiest selves.


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Article written by nutrition intern, Ari Harkavy. Fact checked by Allison Tallman RD.

Sources: 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929498/

https://www.sleepfoundation.org/physical-health/weight-loss-and-sleep https://www.webmd.com/diet/sleep-and-weight-loss

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