How Much Weight Do You Lose Overnight? Insights In 2024

Esther Seun, BSN
Dr. Maya Frankfurt, PhD
How much weight do you lose overnight? Get 2024 insights on how much weight you can lose and why you are lighter after a good night’s sleep.
how much weight do you lose overnight
You can lose weight during sleep. Photo: fizkes/Shutterstock

If you are on a weight loss regimen, you are likely on a diet and exercise routine. You carry all of these out during the day and rest at night. So, why would weight loss happen at all at night?

Your body burns calories around the clock, including when you’re sleeping. If in doubt, try getting on your scale just before bedtime and again when you wake up. You will notice you are lighter in the morning than you were the night before. 

Shockingly, most of the pounds lost do not reflect fat loss alone. Rather, it is mostly due to water loss. You lose water at night through breathing, sweating, and urinating.

So, how much weight do you lose overnight? This article will explore the ways in which weight is lost overnight.

How Much Weight Do You Lose Overnight On Average?

Most of the weight you lose during sleep is water weight via sweat and breathing. You also shed some weight as you burn calories during sleep. So, here’s how much weight you could possibly lose after a good night’s sleep:

  • Approximately 20 mg through sweat.
  • About 500 grams through urine.
  • Some weight through carbon loss and burning calories.

How Much Weight Do You Lose Overnight?

how much weight do you lose overnight
How much weight do you lose overnight? Photo: Leszek Glasner/Shutterstock

Most of the weight you lose during sleep is water weight via sweating and breathing. You also shed some weight as you burn calories during sleep. So how much weight do you lose overnight on average?

Sweat

When a person sleeps, they lose about 25 ml of water per hour at about 85F. The recommended length of sleep is seven to nine hours. So, if a person has eight hours of sleep, they would sweat 200 ml of water. This equals a 20 mg loss in body weight overnight.

Urination

On average, a person makes about 0.5 ml to 1 ml of urine per kilogram of body weight per hour. So if you are 60 kg, you will produce between 240 ml and 480 ml of urine for eight hours of sleep. This could make you lose about half a kilogram of body weight, or 500 grams, if you didn’t consume anything throughout the night and emptied your bladder before stepping on the scale in the morning.

Breathing

The weight lost through breathing is negligible. However, whatever is lost makes you lighter when you wake up in the morning.

Calories Burned During Sleep

The amount of calories you expend while sleeping depends on your body weight, body composition, diet, and other factors. The average person burns at least 50 calories per hour of sleep and 400 calories after eight hours of sleep.

How Does Overnight Weight Loss Happen?

Two forms of weight loss occur during sleep. Water weight loss and carbon dioxide weight loss. 

The water loss is referred to as insensible water loss. Insensible water loss occurs through the body’s normal physiological processes. Studies suggest that 83% of the weight lost during sleep is from breathing and sweating.

When we breathe, we inhale oxygen and exhale carbon dioxide. For every exhalation, two molecules of carbon dioxide are lost. How does this happen?

Our rooms are mostly cooler than our bodies at night. So, when you inhale, you breathe in cool, dry air, and on its way out, it is heated and released with water as vapor. Now, imagine releasing water vapor every minute of the hours you’re asleep.

Additionally, people sweat when they sleep. Although an average person sweats 25 ml per hour and 200 ml in eight hours of sleep, this can vary. Volume can increase due to various factors, including exercise, diet, and health status.

Physical activity during the day increases your core temperature. This can persist until nighttime and make you sweat profusely. Hot meals, hot drinks, and spicy foods can also increase sweating. You may experience heavy sweating if you have a fever or experience night sweats due to a health condition.

Carbon Dioxide Weight Loss

Your body continues to burn calories at rest to keep you alive. Fats and carbohydrates are the main energy sources in the body. Food stores are continually broken down to maintain bodily functions like breathing, blood circulation, cellular growth and repair, temperature regulation, and digestion. 

The number of calories your body requires to maintain itself is called the basal metabolic rate, or BMR. Generally, the basal metabolic rate accounts for about 80% of your total calories expended in a day. Your brain can only use glucose as fuel and this accounts for approximately 20% of your total daily calories at rest.

The number of calories your body requires to maintain itself is called the basal metabolic rate, or BMR. Generally, the basal metabolic rate accounts for about 80% of your total calories expended in a day. Your brain can only use glucose as fuel and this accounts for approximately 20% of your total daily calories at rest.

So you burn about 15% fewer calories while sleeping than during the day. Carbon dioxide is the by-product of these metabolic processes and is exhaled during breathing.

Factors That Affect How Much Weight You Lose

how much weight do you lose overnight
Diet is a factor that affects how much weight you lose. Photo: ViDI Studio/Shutterstock

Multiple factors influence how your body burns calories and how much weight you can lose. 

Genetics

Genetics can influence metabolic rates. They also determine your body’s composition, height, and weight. The bigger you are, the more calories you need to function.

Gender

Males generally have a higher BMR compared to females. This is due to the fact that the proportion of muscle mass is greater in males.[1]

Diet

Muscles help you burn more calories than fat. Increased protein intake is associated with increased muscle mass and healthy weight loss. Studies[2] suggest that consuming a protein-rich diet, especially at night, increases muscle synthesis and metabolism, thus encouraging weight loss.

Exercise

Muscles burn more calories at rest than fat. Hence, people who exercise regularly will have more muscle and lose weight at rest than those who don’t.

Sleep Quality

Sleep deprivation is associated with weight gain and an increased body mass index.[3] Going hours without enough sleep increases the production of hunger hormones. This increases your appetite, makes you eat more, and helps you gain weight.

On the other hand, getting enough sleep regularly promotes weight loss. Getting adequate sleep preserves muscle mass, which increases your BMR.

Medical Conditions

Medical conditions and, in some cases, their treatments can alter your metabolism and affect how much weight you can lose. These include conditions like hyperthyroidism,[4] Grave’s disease,[5] menopause, pregnancy, lactation,[6] and hypothyroidism.

Bedtime Tips For Long-Term Weight Loss 

Sleep is crucial to good health, and a lack of it can make losing weight difficult. To improve your sleep quality and achieve long-term weight loss, try following these simple bedtime tips:

  • Have a regular sleep schedule and stick to it.
  • Create an environment conducive for sleep.
  • Limit late use of electronic devices such as phones, tablets, computers, and TV.
  • Limit alcohol and caffeine intake.
  • Stay hydrated.
  • Take a cold shower before bed.

Conclusion

It is normal to lose weight overnight and wake up lighter in the morning. The amount of weight you’ll lose in a night depends on how much water you lose through excretion.

There is a relationship between sleep and weight loss. If your goal is sustainable weight loss, combine healthy sleep habits with healthy lifestyle choices. These include a balanced diet and exercise.

Frequently Asked Questions

Why do I lose 2 pounds overnight?

Losing weight over the night can be due to several factors, including diet, health status, and exercise. It can also indicate an underlying medical condition, such as hyperthyroidism.

Is it normal to lose 5 pounds overnight?

No, it’s not. However, the human body can lose more than three pounds daily. However, a 5-pound weight loss overnight is for people who are critically overweight.

Can you slim down overnight?

Yes, you can. You can lose weight overnight by practicing healthy sleep habits, developing healthy dietary habits, and building muscle to boost your metabolism.

How should I sleep to wake up skinny?

Sources suggest that sleeping on your left side aids digestion, prevents fat accumulation, and helps you lose weight. However, research is limited.

How should I eat before bed to lose fat?

You need to practice mindful eating. Eat only small portions of a high-protein diet. Avoid caffeine, alcohol, high-fat foods, spicy foods, and chocolate. Also, avoid eating late in the evening.

Can a supplement make me lose weight overnight?

Combining a good night’s sleep with a fat burner supplement can make you shed some weight overnight.

Do hormones affect weight loss during sleep?

Yes, they do. High levels of cortisol and ghrelin promote weight gain,[7] while higher amounts of leptin cause weight loss.[8] So, it’s important to balance hormones to lose weight.

How do I fall asleep fast?

Relaxation is crucial to falling asleep quickly. Visualization, meditation, and reducing your room’s temperature are strategies that can help you fall asleep fast.

Resources

  1. Bredella, M.A. (2017). Sex Differences in Body Composition. Advances in Experimental Medicine and Biology, [online] pp.9–27. doi:https://doi.org/10.1007/978-3-319-70178-3_2.
  2. Ralf Jäger, Kerksick, C.M., Campbell, B., Cribb, P.J., Wells, S., Skwiat, T.M., Purpura, M., Ziegenfuss, T.N., Ferrando, A.A., Arent, S.M., Smith‐Ryan, A.E., Stout, J.R., Arciero, P.J., Ormsbee, M.J., Taylor, L., Wilborn, C., Kalman, D., Kreider, R.B., Willoughby, D.S. and Hoffman, J.R. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition, [online] 14(1). doi:https://doi.org/10.1186/s12970-017-0177-8.
  3. Evangelia Papatriantafyllou, Dimitris Efthymiou, Evangelos Zoumbaneas, Codruța Alina Popescu and Εmilia Vassilopoulou (2022). Sleep Deprivation: Effects on Weight Loss and Weight Loss Maintenance. Nutrients, [online] 14(8), pp.1549–1549. doi:https://doi.org/10.3390/nu14081549.
  4. Jesper Karmisholt, Carlé, A. and Andersen, S. (2020). Body Weight Changes in Hyperthyroidism: Timing and Possible Explanations during a One Year Repeated Measurement Study. European thyroid journal, [online] 10(3), pp.208–214. doi:https://doi.org/10.1159/000512078.
  5. Cai, Z., Chen, Q. and Ling, Y. (2022). Weight Gain and Body Composition Changes during the Transition of Thyroid Function in Patients with Graves’ Disease Undergoing Radioiodine Treatment. International Journal of Endocrinology, [online] 2022, pp.1–9. doi:https://doi.org/10.1155/2022/5263973.
  6. Foster, S., Vazquez, C., Cubbin, C., Nichols, A.B., Rickman, R. and Widen, E.M. (2023). Breastfeeding, socioeconomic status, and long-term postpartum weight retention. International Breastfeeding Journal, [online] 18(1). doi:https://doi.org/10.1186/s13006-022-00534-0.
  7. Chao, A.M., Jastreboff, A.M., White, M.A., Grilo, C.M. and Sinha, R. (2017). Stress, cortisol, and other appetite-related hormones: Prospective prediction of 6-month changes in food cravings and weight. Obesity, [online] 25(4), pp.713–720. doi:https://doi.org/10.1002/oby.21790.
  8. Pereira, S., Cline, D.L., Glavas, M.M., Covey, S.D. and Kieffer, T.J. (2020). Tissue-Specific Effects of Leptin on Glucose and Lipid Metabolism. Endocrine Reviews, [online] 42(1), pp.1–28. doi:https://doi.org/10.1210/endrev/bnaa027.

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