It’s a common belief that you can lose weight while you sleep. The idea is that when you’re asleep, you’re fasting and not eating any calories. Additionally, your metabolic rate slows down during sleep, meaning you burn fewer calories. So it would make sense that you’d lose weight overnight, right?
The truth is, it’s not that simple. There are a variety of factors that determine whether you lose weight while sleeping. Understanding the science behind sleep and metabolism can help explain what’s really happening when you hit the hay.
Do you burn calories while sleeping?
Yes, you do burn calories while you sleep. The number of calories you burn depends on your basal metabolic rate (BMR), which is the number of calories your body needs to perform basic, life-sustaining functions.
Your BMR accounts for 60-75% of the total calories you burn each day. It’s determined by factors like your age, sex, body size and composition. People with more muscle mass tend to have a higher BMR.
Here’s an overview of how many calories you can expect to burn per hour of sleep based on your age and sex:
| Age | Men | Women |
|---|---|---|
| 20 years | 63-73 calories | 52-62 calories |
| 30 years | 61-71 calories | 49-59 calories |
| 40 years | 59-68 calories | 47-56 calories |
| 50 years | 56-64 calories | 44-53 calories |
| 60 years | 53-61 calories | 41-49 calories |
| 70 years | 49-58 calories | 38-46 calories |
As you can see, the number of calories you burn decreases as you get older. But even if you’re sleeping for 8 hours, you’ll still burn hundreds of calories.
So while you’re asleep, your body is still burning calories to keep basic functions going. But other factors determine whether sleeping results in weight loss.
Does your metabolism slow down during sleep?
Yes, your basal metabolic rate slows down significantly when you’re sleeping.
During wakefulness, your BMR is affected by physical activity, diet-induced thermogenesis (the energy cost of digesting food), and maintaining an upright posture.
At night, your body doesn’t need as much energy for these functions, so your metabolism can slow down by around 5-10%.
Studies show mixed results on how much metabolic rate decreases during sleep. In one study, participants’ BMR decreased by 7-8% during early non-REM sleep and 9-10% during later REM sleep:
| Sleep stage | Drop in metabolic rate |
|---|---|
| Wakefulness | Baseline |
| Early non-REM sleep | 7-8% decrease |
| Late non-REM sleep | 8-9% decrease |
| REM sleep | 9-10% decrease |
So you burn slightly fewer calories when sleeping compared to being awake. But the decrease in metabolic rate is fairly small and doesn’t outweigh the benefits of getting adequate rest.
Does sleeping longer lead to more weight loss?
You might think that sleeping more hours would equal more weight loss, but it’s not that simple. Studies show conflicting results on whether extended sleep is helpful or harmful for weight management.
Some research has found a link between short sleep duration (less than 7 hours per night) and increased obesity risk:
– In one study, people who slept 5 hours per night were 73% more likely to become obese over a 5-16 year period compared to those who slept 7-8 hours per night.
– Another study found sleeping 5 or fewer hours per night doubled the risk of becoming obese in both children and adults.
However, other studies show no difference in weight between short and long sleepers. And some research suggests sleeping more than 9 hours per night is associated with weight gain.
Potential reasons why too much sleep could lead to weight gain include:
– Increased appetite – sleep impacts hormones that regulate hunger and fullness.
– Decreased physical activity – being in bed more gives you less time to exercise.
– Disrupted metabolism – excessively long sleep may alter daily rhythms in a way that promotes weight gain.
Overall, aim for 7-9 hours of sleep per night. Getting adequate rest is crucial for your health. But simply sleeping longer won’t necessarily lead to losing more weight.
Can sleep quality impact weight?
It’s not just sleep duration that matters – sleep quality plays a role too. Poor sleep quality can interfere with healthy weight maintenance.
Sleep disorders like insomnia have been associated with increased risk of obesity and weight gain over time:
– One review found that adults with insomnia were 1.3 times more likely to develop obesity compared to those without insomnia.
– Another study found that postmenopausal women who reported frequent insomnia symptoms had gains in visceral fat over time.
Poor sleep quality can impact weight by:
– Increasing appetite – lack of sleep alters hormones that regulate hunger.
– Causing cravings – too little sleep triggers cravings for junk food high in carbs and fat.
– Slowing metabolism – fragmented sleep may decrease resting metabolic rate.
– Increasing fatigue – being tired from poor sleep can reduce motivation for activity and exercise.
Ways to improve sleep quality include:
– Following a regular sleep-wake schedule.
– Making sure your bedroom is cool, dark and quiet.
– Avoiding screens before bedtime.
– Doing relaxing activities before bed like taking a bath, reading or light yoga.
– Practicing sleep hygiene habits like avoiding large meals before bed.
Prioritizing restful, uninterrupted sleep is crucial for overall health, including maintaining a healthy weight.
Can certain foods or drinks before bed affect weight loss?
Yes, what you consume before bed can influence weight loss during sleep. Some foods and drinks support restful sleep and metabolism, while others can interfere with weight management.
Here are some dos and don’ts for eating and drinking before bed for weight loss:
DO:
– Drink chamomile tea – Compounds in chamomile tea may promote sleepiness and relaxation.
– Have a light snack like turkey, hummus and veggies – Tryptophan in turkey can make you sleepy.
– Eat fatty fish like salmon – Omega-3 fats may improve metabolic factors tied to obesity.
– Sip tart cherry juice – Cherry juice is linked to less insomnia and improved sleep quality.
DON’T:
– Drink alcohol – Alcohol disrupts sleep patterns and decreases fat burning.
– Eat salty, fatty and sugary foods – These can negatively impact sleep quality and promote weight gain.
– Drink soda, coffee or energy drinks – The caffeine interferes with the body’s sleep-wake cycle.
– Have a heavy, spicy meal – Hard to digest foods can lead to indigestion and sleep issues.
Making smart food choices at night optimizes your ability to get deep, restorative sleep and prevents weight gain.
Does exercise before bed help or hurt weight loss?
Exercising is important for weight management. But the timing of your workout could affect whether you lose weight during sleep.
Here is how exercise before bed may impact weight loss:
Potential benefits:
– Raises body temperature – The post-exercise rise in temperature could increase metabolism during sleep.
– Induces sleepiness – The physical exertion may help you fall asleep faster.
– Reduces stress – Exercise relieves anxiety and depression which can aid sleep.
Potential downsides:
– Interferes with sleep – Exercising close to bedtime can disrupt sleep onset and quality due to increased heart rate, body temperature and hormones.
– Increases appetite – Nighttime exercise may cause unnecessary hunger and cravings, especially for unhealthy foods.
– Delays metabolism – Intense training before bed may prevent your metabolic rate from dropping normally at night.
The best time to work out for weight loss is in the afternoon or early evening. This allows your body temperature and hormones to return to normal before bed.
Aim to finish moderate to intense exercise at least 3 hours before sleep for best results. Light yoga or stretching immediately before bed is unlikely to interfere with sleep or metabolism.
Should you weigh yourself before bed and in the morning?
It’s common advice to weigh yourself first thing in the morning after using the bathroom and before eating or drinking anything.
This is the most accurate and consistent time to track your weight from day to day.
Weighing yourself before bed may show a higher number due to:
– Food and beverages consumed throughout the day.
– Waste in your digestive system.
– Fluctuations in water weight.
– Clothes and shoes adding extra weight.
However, checking your weight at night and in the morning can provide insight into how your body changes during sleep.
You may notice a dip in your nighttime weight for a few reasons:
– Loss of water weight from sweat and breathing out water vapor.
– Burning some calories overnight.
– Loss of waste from urinating.
But this doesn’t necessarily represent fat loss. Your nighttime weight will likely rebound in the morning after eating and drinking.
While interesting, keep in mind that your morning weight provides the most meaningful data point regarding your weight loss progress.
Tips to lose more weight during sleep
Here are some helpful tips to support healthy weight loss while you’re sleeping:
– Don’t eat within 2-3 hours of bed – This prevents indigestion and metabolic disturbances from trying to digest food as you sleep.
– Have a light protein-based snack before bed – Protein provides amino acids to help maintain muscle mass overnight.
– Stay well-hydrated during the day – This prevents excessive water loss leading to dry mouth or nighttime bathroom trips.
– Sleep in a cool room – Sleeping in a cold environment can increase calorie burn slightly.
– Get enough magnesium – Magnesium deficiency is linked to poor sleep quality and insomnia.
– Take a relaxing bath – A warm bath can help lower cortisol to promote sleepiness.
– Limit alcohol – Drinking alcohol before bed disrupts sleep cycles and suppresses fat burning.
– Prioritize consistent sleep times – Keeping a regular sleep-wake cycle optimizes your circadian rhythms.
– Don’t overdo late-night exercise – Moderate activity earlier in the day is best for sleep and metabolism.
Focus on supporting high-quality, restful sleep rather than simply more sleep. Adequate sleep and healthy lifestyle habits are key for successful weight management.
The bottom line
You do burn some calories while sleeping due to your basal metabolic rate. However, your metabolism only slows down by about 5-10% during sleep.
While you can lose a small amount of weight overnight, extended sleep doesn’t necessarily lead to more weight loss. Too much sleep may even be counterproductive.
The quality of your sleep is just as important as the quantity. Disrupted, poor-quality sleep can interfere with weight maintenance and even contribute to weight gain over time.
Eating a light, protein-rich snack, staying hydrated and avoiding heavy late-night meals or exercise can support weight loss during quality sleep.
Aim for 7-9 hours of uninterrupted sleep in a cool, comfortable environment to get the benefits of restful sleep for overall health and weight management.