Do You Lose Weight While You Sleep?


Written by Leigh Saner

Reviewed by Dr. Michael Breus

Our Editorial Process

Table of Contents

There are many benefits to getting a restful night’s sleep. People who get adequate sleep each night and wake feeling rested perform better at work and school, avoid accidents, have improved mental health and less stress, and may lower their risk for some chronic health conditions, including obesity. 

Obesity is an increasingly common chronic health condition in the United States. Over 40% of American adults live with obesity. Health concerns that are linked with obesity include type 2 diabetes, heart health issues, and sleep apnea

Research shows a clear association between obesity and lack of sleep. However, there is no evidence to support that sleeping more or getting the recommended amount of sleep promotes weight loss. We discuss the connection between sleep and weight as well as general tips for improving your sleep health.

How Do You Lose Weight While Sleeping?

The human body loses weight during sleep primarily because of water loss. However, day to day weight fluctuations are different from long-term weight loss.

On a daily basis, including during sleep, the average person loses just under 1 liter of water as it evaporates from the skin and through breathing. Water loss also occurs as the body makes and eliminates urine, which can also temporarily affect body weight. 

The relationship between sleep and weight loss is complex. While water loss may cause temporary fluctuations in weight, many factors play a role in long-term weight loss including hormones, food intake, daily physical activity, and even sleep habits.

While daytime activities do require more calories, sleeping uses some energy. During sleep, the body continues to burn calories to maintain essential functions. However, there is no evidence to suggest sleeping burns enough calories to cause meaningful weight loss.

While more research is needed, experts believe that maintaining healthy sleep habits is important for maintaining body weight and avoiding some of the complications that arise with obesity.

Can Poor Sleep Impact Weight?

Over the last several decades, obesity rates have increased, while the average amount of sleep that American adults get per night has decreased. While obesity is likely due to many more factors than just sleep, some research shows that poor sleep may, at least, in part, play some role in a higher body weight. 

While experts think too much sleep may possibly be related to weight gain, research is more consistently finding sleep deprivation to be a risk factor for higher body mass. In addition, experts continue to find healthy sleep habits to be associated with overall better health, including a healthy body weight.

Experts remain uncertain about the underlying reasons behind why inadequate sleep may be associated with body weight, though they suspect several factors may be involved.

  • Diet choices: Studies suggest that those who sleep less may also make certain food choices. This can include increased food intake, a preference for energy dense foods, more snacking, and irregular meal patterns. 
  • More time to eat: Staying awake for longer periods of time allows people more time to eat, rather than sleep. Some experts believe that people who sleep less may eat higher amounts of food overall.
  • Less physical activity during the day: Physical activity plays a role in supporting a healthy weight. Experts think that those who sleep less may be more tired and less active during the day. Less daily activity can lead to lower energy expenditure, which can affect a person’s weight.
  • Insulin resistance: Research shows that lack of sleep, staying up at night, and eating at night may be risk factors for excess insulin and a lower sensitivity to insulin. This can cause insulin resistance, which is associated with type 2 diabetes and difficulties with weight control.
  • Changes in hunger hormone levels: While data on this topic remains mixed, some research shows that shorter sleep is associated with decreased levels of the anti-hunger hormone, leptin, and increased levels of the hunger-promoting hormone, ghrelin. Sleepers who sleep for less time at night may eat more overall.
  • Other shifts to metabolism: There are many factors involved in how people burn energy, and experts believe factors like the nervous system and hormones are impacted by sleep habits. Short sleep duration, night work, and other sleep disruptions may cause additional shifts to metabolism that could negatively impact body weight.

Can Sleeping Well Encourage Weight Loss?

Some research suggests that obtaining adequate amounts of sleep may encourage weight loss in some people with obesity. However, there is no evidence to support the claim that sleeping well promotes weight loss more generally. 

While researchers are not entirely certain why healthy sleep may impact weight, they do think it may be due to several reasons such as less overall food intake, better quality of food choices, improved physical activity levels, and proper metabolic functioning.

Getting adequate sleep helps people maintain leptin and ghrelin levels, which can help a person know when they are hungry or full, preventing them from overeating. In addition, there is evidence to suggest that people who get enough sleep don’t require as much energy from fats and carbohydrates.

Understanding your natural chronotype may help you optimize your schedule and sleep habits.

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How to Improve Sleep and Boost Health

Developing and maintaining healthy sleep hygiene habits can help you improve your sleep.  

  • Go to bed and wake up at the same time every day: Following a consistent sleep schedule, both during the week and on weekends, will make it easier to establish healthy sleep habits. 
  • Get the recommended number of hours of sleep per night: Research shows an association between inadequate sleep and chronic health concerns, including obesity. For adults, the recommended hours of sleep per night ranges from seven to nine hours. 
  • Limit caffeine intake: Consuming caffeine within the hours leading up to bed can negatively impact sleep quality. If you drink caffeinated beverages like soda, tea, or energy drinks, try to avoid them beginning in the afternoon hours and leading up to bedtime. 
  • Exercise: Exercise is an important part of a healthy lifestyle including losing or maintaining weight. Experts suggested finding time to exercise for at least 30 minutes most days. However, exercising within two to three hours of bedtime can be disruptive to sleep. 
  • Limit alcohol intake close to bedtime: Alcohol consumption close to bedtime can lead to nighttime awakenings and less deep sleep. For some people, drinking in the evening and before bed can affect their breathing during sleep. 
  • Avoid large meals close to bedtime: Consuming larger meals closer to bedtime can cause digestive issues that disrupt sleep. Large meals late in the day can also disrupt the body’s natural circadian rhythms. Studies show that people who eat later in the evening have a higher body fat percentage and greater risk of developing diabetes. 
  • Find time to relax before bed: A bedtime routine that includes time for relaxation can help you prepare for a restful night’s sleep. Activities such as taking a warm bath, relaxation exercises, or reading help some unwind from the day. 
  • Keep the bedroom temperature cool: Although the body responds well to a warm bath before bedtime, a cool temperature in your sleep area is often better for rest. Most people find a room temperature ranging from about 65 to 68 degrees Fahrenheit to be most comfortable for sleep.
  • Get rid of lights in the bedroom: Exposure to light in the bedroom, especially blue light from electronic devices, can impact your ability to fall asleep. Your body has an internal clock that uses cues such as light to determine when it’s time to sleep and time to be awake. Exposure to light close to bedtime can disrupt this clock and delay sleep.
  • Get sunlight throughout the day: Experts recommend spending time outside in the morning, or during the earlier parts of the day. Exposure to natural light outdoors during the early part of the day can help you feel sleepy at night when it’s time to go to bed. 
  • Limit how long you lie in bed awake: If you can’t fall asleep within 20 minutes of lying down, consider getting out of bed and reading a book or doing another relaxing activity until you feel sleepy. 

About The Author

Leigh Saner

Staff Writer

Leigh is a freelance wellness writer and a national board-certified health and wellness coach based in Greenville, North Carolina. With a master’s degree in public health, she has been a coordinator of health services at the Edgecombe County Health Department in North Carolina. She enjoys researching health information and synthesizing it to support health literacy and well-being. Leigh is particularly passionate about providing practical ways for people to reduce stress and adopt healthy lifestyle practices to improve sleep quality.

  • POSITION: Side Sleeper
  • TEMPERATURE: Neutral Sleeper
  • CHRONOTYPE: Dolphin

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