The Surprising Connection Between Sleep and Weight Loss

Let us discuss the interesting connection between sleep and weight loss. For the last decades, there are more and more different diets popping up on the market to reduce weight and actually lose all the excess fat, but what if the actual secret is in your sleep routine? What if we tell you that by sleeping more hours you could lose weight? 

How about we dive deeper into this and figure out what is behind this science or if it is only a presumption?

Going back to 2018, a study published in the ¨Journal of Sleep¨ found that people with normal, healthy sleep schedules burn more fat, which is backed up by different metabolic changes in the brain and body that occur when we sleep.

We all know that sleep is crucial for your general health – but it is also for weight loss. Being on a weight loss journey, you probably even notice that you lose a couple of grams/lbs after a restful sleep, as you also burn calories while you sleep.

Let us break that down to get a better picture: 

The body requires enough sleep for recovery of all body functions, including the renewal of cells, digesting food, absorbing and storing nutrients, but also to simply keep all vital functions going while we rest. While you are not consciously moving, your body yet continues functioning. Your heart is still pumping blood and your lungs are still breathing because during this time your autonomic nervous system is active. Related to weight loss, 83% of the weight we lose during sleep is water, which is eliminated through breathing, transpiration, and excretion.

We have different sleep phases and one of them is Rapid Eye Movement (REM) where your heart rate increases and brain activity patterns mimic daytime levels. During this time, which is our most profound sleeping phase, we usually have very vivid dreams and the brain activity we use requires more glucose. Glucose is the blood sugar that gives us energy. If the blood sugar level is too low, automatically our body engages our fat depots to release the stored sugar from the pancreas or the sugar which is stored in and also creates the fat cells. Your body undergoes different physiologic processes and is burning up calories without taking in food as fuel. Instead, it uses glucose and stored fat as fuel during your sleep.

This increased physiologic activity during sleep therefore also increases our metabolism. 

Brown Fat Activation

We have two different kinds of fat- the white fat cells which store glucose for energy and the brown fat cells which break down glucose and fat molecules to create heat and help maintain body temperature.

Sleeping in a cool environment activates brown fat cells and burns them to regulate your body temperature. It helps you regulate glucose and fat metabolism

Researchers recommend 17 to 19 degrees celsius at room temperature to activate the brown fat. Also taking cold showers or an ice bath increases this fat burn to regulate your body’s temperature. The brown fat activates at colder temperatures, right before you start shivering. 

So, How Many Calories Can You Burn While You Sleep?

We burn around 50 calories an hour, when we sleep 8 hours of sleep this is roughly 400 calories!

But keep in mind this can vary from each person and depends on your lifestyle and physiology.

Here we also add an article by Harvard Medical School talking about other non-exercising activities: Burning calories without exercise – Harvard Health

Can You Increase The Number Of Calories You Burn While You Sleep?

According to the Sleep Foundation, you need to increase your basal metabolic rate (BMR). The BMR refers to the energy needed for normal functions like breathing, circulation, temperature regulation, and cellular growth and repair. Regular exercise, eating healthy foods, and a regular sleeping schedule can increase BMR so that calories burned while sleeping increase.

For this, you can also use a sleep fat burner, to promote more restful sleep.  

How To Calculate Calories Burned While Sleeping?

The metabolic rate is around 15% lower when a person is asleep than when they are awake and reaches a minimum in the morning in a standard circadian pattern. 

For females: The BMR = 665.1 + (4.34 x weight in pounds) + (4.7 x height in inches) – (4.68 x age in years)

For males. The BMR = 66.47 + (6.24 x weight in pounds) + (12.71 x height in inches) – (6.78 x age in years)

The calories burned while sleeping equals (BMR / 24) x number of hours asleep x 0.85

Follow this link below for more insights and information: Calories burned while sleeping: How to calculate

Can Improving Sleep Health Promote Weight Loss?

Improving your sleep health is associated with a healthy weight and healthy eating behaviour, as your body is more in balance and the food intake is regulated better and can be digested probably.

A 2021 study even found that people with sleep apnoea lost more body weight and fat when they experienced better sleep.

In general people’s sleep requirements vary, but research has observed changes in weight when people get fewer than 7 hours of quality sleep a night. This poor quality of sleep has repeatedly been linked to a higher body mass index (BMI).

We can take from this, that you may feel more tired during the day as you lack the energy to work out, and as a midday low sets in that also your physical activity is decreased- leading here to weight gain as a result of deprived sleep and not being active enough. 

Can Disrupted Sleeping Patterns Affect Weight Loss?

The easy logic upfront, sleeping fewer hours means you have more time to eat. 

But one of the reasons for this connection between sleep and weight loss is the effect that sleep deprivation has on appetite regulation. Sleep deprivation is known to disrupt the hormones that regulate hunger and satiety, leading to increased appetite and food intake. 

A shorter sleep interval is associated with stress eating and hedonic eating.

It can cause you to make poorer food choices, and therefore brings a higher calorie intake along or even increase hunger when junk food is consumed. Most likely you tend to crave high-calorie, high-fat foods which lead to binge eating but don’t fill you up with nutritional value. This ultimately even leads to weight gain.

Research shows you rack up more calories and eat less healthy food when you are sleep deprived, here we talk about less than 7 hours of sleep a night. 

So keep in mind that a poor sleep routine is not only a major risk factor for weight gain but can also lead to obesity because different hormones have a negative response to a lack of sleep. 

The Body-Clock

The circadian rhythm (body clock) is our inner setting on time as to when and which organ is under ¨maintenance¨ during the night. A wide variety of physiological events including the metabolism in all organisms are controlled by it. External cues like being influenced by daylight and darkness in the night to create a 24-hour rhythm of being awake and asleep are the body’s way of adaptation.

Working different shifts can set off this rhythm and create a conflict with the sun’s light/dark cycle hence creating a metabolic imbalance such as in the body temperature, digestion, heart rate, blood pressure, hormones, and neurotransmitter secretion. Having an unregulated sleep pattern, for example, due to different work schedules or just staying up at night for long hours has an overall negative effect on the body regulations, as the body clock is set off. Therefore it is recommended to create a good 8-hour sleep routine, going to bed before midnight and rising with the sun, which would be the optimal way. In this way, your body can proceed in its own natural way.

From the hormonal perspective, there are also a lot of changes. Let us see what is happening: 

Decrease in Leptin

A loss of sleep triggers a decrease in Leptin. Lower levels of leptin signal your brain that you are in starvation mode which forces your brain to start looking for ways to conserve energy. Hence you eat more, and your body hangs on to your fats even more for survival.

Decrease Insulin Sensitivity

It impairs insulin sensitivity, meaning less glucose is being used by different cells in the body. Muscles use 20-30% less glucose (blood sugar) when sleep is deprived. The body stores unused glucose from the blood as fat, causing weight gain.

Increase Cortisol

Cortisol is a stress hormone and high cortisol prompts the body to store more fat and use more muscle for energy. Sleep-deprived dieters lose more muscle and gain more fat than those who are well-rested.

Increase in ghrelin

This hormone is produced by your stomach. The higher your levels of ghrelin, the hungrier you get. There are stimulatory effects on food intake, fat deposition and growth hormone release and ghrelin is known as the “hunger hormone”. A lack of sleep triggers the release of more ghrelin and is making food more enticing, and increasing appetite.

Decrease in serotonin

Serotonin is your brain’s neurotransmitter for happiness and most of the serotonin found in your body is in your gut (intestines) about 90% of serotonin is found in the cells lining your gastrointestinal tract. In the case when we have less serotonin it means you look for more comfort food (sweets, junk foods, etc.) to compensate for instant satisfaction and raise your mood, as a low level is related to depression, anxiety, mania, and other health conditions.

How much sleep do you need to support weight loss?

A complete 8 hours of sleep each night is the ideal amount of time to have a healthy rest for the human body – preferably uninterrupted and restful. If you have a regular good sleep routine it will support your regeneration and your body works to your advantage. 

Tips For Healthy Sleep Patterns To Promote Weight Loss

  • Doing a ¨Digital Sunset¨- means: avoiding using your electronic devices 1-2 hours before bedtime, so your body tunes into a relaxed mindset, without an overload of information and stimulation.
  • Sleep in a dark room so the production of melatonin, the sleep-inducing hormone, can operate properly. Where exposure to light suppresses the production of melatonin. In addition, sleeping in a dark room helps to reset our body clocks, also called our circadian rhythms.
  • Go to bed and wake up at the same time every day, even on weekends. That creates a rhythm for your inner body clock and is ideal for proper body functions and recovery during the night. 
  • Avoid caffeine and alcohol serval hours before sleep, best not to drink them at all, as your body still needs time to detox these substances. 
  • Use sleep fat burners for more restful sleep. Those can be lean PM which contains melatonin that improves sleep quality and promotes restful sleep while burning fat.
  • Avoid eating heavy meals one to two hours before bedtime. So that you do not feel heavy going to bed, and your body is not busy with digesting food but to recover and repair.  
  • Exercise regularly, so your metabolism is working optimally, and the fat-burning mechanism is active.  


A healthy sleep routine is as essential as healthy nutrition and being active. To have the best outcome on your weight loss journey, make sure you have sufficient rest at night- optimally 8 hours of sleep in a dark room, in a cooler environment of around 17 to 19 degrees Celsius. This should be an important part of a healthy weight loss plan. 

And keep in mind that losing sleep and following an unregular sleep schedule while dieting can reduce the amount of weight loss and encourage overeating, which does not work in your favour. Furthermore, if you want to support your body, we prepared a link for you with more information on how these ¨sleep fat burners ¨ work and recommendations of our favourite product.

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Dr. Ahmed Zayed holds a bachelor’s degree in medicine from Alexandria university and is a practicing plastic surgeon. He’s our expert on all things nutrition, medicine, rehabilitation, and flexibility. Dr.Ahmed has been a medical content writer for more than 11 years and his work reached top publications such as the HuffingtonPost

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