Despite what popular weight loss diets suggest, most weight lost while sleeping is water weight. You can combine healthy sleep habits with a balanced diet and exercise routine to help lose weight more long-term.

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The global obesity epidemic has fueled a sharp rise in efforts to find effective and accessible weight loss strategies.

As a result, new diet trends are constantly flooding the market, some of which promise to help you shed pounds while you sleep.

This article explores if you can lose weight overnight and how you may use your sleep pattern to promote healthy and sustainable weight loss.

Water weight

If you’ve ever tracked your weight, you may have noticed that you weigh a little less in the morning than later in the day.

This is why many people prefer to weigh themselves in the morning, although that lower scale number is not a result of fat loss alone. Rather, it’s likely more reflective of water loss.

That’s not to say you don’t burn calories overnight. When you sleep, your body must fuel the complex metabolic processes that keep you alive and healthy. Meanwhile, you also lose water through your breath and sweat (1, 2).

A single cup (237 ml) of water weighs close to 1/2 pound (240 grams). Your body comprises about 55–75% water, which accounts for a significant proportion of your weight (2, 3).

According to some estimates, over 80% of overnight weight loss may be due to water loss. That said, how much you lose while sleeping varies depending on your body composition and metabolic rate (4).

Most of your overnight weight loss can be attributed to the water you lose through sweating and breathing.

Sleep quality and duration

Though many of the most effective weight loss strategies focus on diet and exercise alone, early research suggests that the quality and quantity of your sleep may also play a big role in your body’s ability to regulate its weight.

Several population based studies have found an association between chronic sleep deprivation and higher body mass index (BMI), which is an indicator of your weight in relation to your height (1).

One study in adults aged 67–99 found that those who slept 5 or fewer hours per night were, on average, 3 times more likely to develop obesity, compared with those who got 7–8 hours of sleep per night (5).

Thus, it may be worth prioritizing adequate sleep as part of your weight loss plan.

Sleep habits can impact hunger hormones

The link between sleep and body weight may partly be explained by how sleep deprivation affects your body’s production of hunger hormones.

Leptin and ghrelin are hormones that regulate feelings of hunger and fullness. Leptin is released by fat cells and works to suppress appetite, while ghrelin is released by the stomach and makes you feel hungry (1).

Ideally, these hormones work together to let you know when you need more energy and when you’ve consumed enough calories. However, some research suggests that without adequate sleep, the balance between the two may become disrupted.

One small study in 12 healthy men found that sleep deprivation decreased circulating leptin by 18% and increased ghrelin production by 28%, leading to a 23% increase in appetite (6).

Furthermore, some studies suggest that you crave highly palatable foods, including calorie dense treats like sweets and salty snacks, when your sleep is poor (1).

When combined, changes in hormone production, appetite, and cravings induced by inadequate sleep may contribute to increased weight and obesity risk.

Still, the relationship between these factors is unclear, and more research is needed to better understand how healthy sleep patterns may be used alongside a balanced diet and exercise plan to promote safe, sustainable weight loss.

Poor sleep patterns are associated with an increased risk of obesity. This may be due to changes in the levels of hormones that regulate your hunger and appetite. Yet, more research is needed.

Improving your bedtime routine can support long-term weight loss

Implementing a healthy bedtime routine can be a great way to support your long-term weight loss goals.

Setting a schedule, cultivating a calming bedtime ritual, and creating a relaxing environment can help improve the quality of your sleep.

Stick to a schedule

A constant flood of information and activities coupled with the demand for productivity can make implementing a sleep schedule difficult, but research suggests it may be worth your efforts.

One study linked irregular sleep patterns to circadian rhythm disruption and impaired sleep quality, regardless of the total time spent sleeping (7).

Thus, setting a bedtime and sticking to it — even on weekends — may be a simple and effective way to improve your sleep quality.

Use relaxation techniques

Even if you’re making an effort to go to bed at the same time each night, falling asleep can present a challenge of its own.

Here are a few simple activities that may help you fall asleep quicker:

• meditate (8)
• have a cup of chamomile tea (9)
• play soothing music (10)
• practice deep-breathing exercises (11)
• discover aromatherapy (12)

If you find it difficult to quiet your mind before bed, consider implementing a bedtime ritual using one or more of these techniques to calm down and prepare your brain for sleep.

Turn off the lights

Melatonin is a hormone that helps regulate sleep-wake cycles by telling your body when it’s time to sleep (13).

How much melatonin your brain produces is strongly influenced by light exposure. In particular, blue light, such as that from the sun, LEDs, and fluorescent lights, hinders melatonin production more than red light (14).

You can support melatonin production and help your body better prepare for sleep by dimming the lights in your home an hour or two before you plan to go to bed.

Computer monitors, televisions, and smartphones significantly contribute to blue light exposure, so you can also try to avoid using these devices before bed. Instead, try reading a book or listening to a podcast to wind down.

Lower the temperature

The temperature in your bedroom may also affect your sleep quality.

Your body temperature naturally decreases in preparation for sleep and rises when it’s time to wake up. If your room is too warm, it may be more difficult for your body to enter the sleep phase, making it harder to fall or stay asleep (15).

Some research suggests that the ideal room temperature to support sleep is 66–70°F (19–21°C) (16).

If you can control the temperature in your bedroom, try knocking your thermostat down a few notches to enhance your sleep quality.

You can improve the quality of your sleep by regulating your bedtime, reducing your bedroom temperature, limiting pre-sleep light exposure, and implementing a relaxation ritual to help you fall asleep quicker.

The bottom line

Some popular weight loss diets suggest that you can lose weight while sleeping. However, the majority of the weight you lose while sleeping may be water weight.

That said, getting adequate sleep regularly may promote long-term weight loss.

To improve your sleep quality, try implementing simple strategies like setting a regular bedtime, reducing light exposure before bed, and creating a peaceful, sleep-promoting environment at home.

If your goal is to lose weight in a sustainable way, make sure to combine healthy sleep habits with a balanced diet and exercise routine.