How to Lose Belly Fat Overnight? Sleep Doctor’s Advice

Want to lose belly fat in your sleep? Focus on lowering your sleep debt and getting in sync with your circadian rhythm to make it easier.
Updated
2024-04-19
17 MINS
Written by
Jeff Kahn, M.S., Rise Science Co-Founder
Reviewed by
Chester Wu, MD, Rise Science Medical Reviewer
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We bring sleep research out of the lab and into your life. Every post begins with peer-reviewed studies — not third-party sources — to make sure we only share advice that can be defended to a room full of sleep scientists.
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Updated Regularly
We regularly update our articles to explain the latest research and shifts in scientific consensus in a simple and actionable way.

How to Lose Belly Fat Overnight? 

  • You can lose belly fat overnight by making sure you’re getting enough sleep for you and getting this sleep in sync with your circadian rhythm, or body clock. 
  • To lose belly fat, you can also eat a balanced diet, avoid eating too late in the day, exercise, cut down on alcohol, and reduce your stress levels. 
  • Getting enough sleep and staying in sync with your circadian rhythm can make other weight loss habits (like avoiding processed foods and staying active) much easier to do. And many healthy changes you make to your diet and lifestyle will benefit your sleep.  
  • The RISE app can work out how much sleep you personally need, calculate and keep track of your sleep debt (how much sleep you owe your body), and predict the timing of your circadian rhythm so you can get and stay in sync.

Out of all the excess body fat we can have, belly fat is the one many people hate the most. But, beyond looks, belly fat is also the most dangerous type of fat. It can also be some of the hardest to lose, and it can be caused by much more than a bad diet. 

Below, we’ll dive into how you can lose belly fat overnight — or at least, start working towards it night after night. 

We explain how to get a flat stomach, what causes belly fat, and how the RISE app can make losing weight easier to do.

Advice From a Sleep Doctor

Advice From a Sleep Doctor

“Sleep is an often overlooked part of weight loss,” says Rise Science sleep advisor and medical reviewer Dr. Chester Wu, who is double board certified in psychiatry and sleep medicine.

“If you’re trying to lose belly fat, try to prioritize getting enough sleep and keeping a regular sleep schedule to boost your weight loss efforts.”

How Can I Lose Belly Fat Overnight?

You can lose belly fat overnight by getting enough sleep for you, syncing up with your circadian rhythm, maintaining good sleep hygiene, eating a balanced diet, not eating too late in the day, exercising, cutting down on alcohol, and reducing stress. 

You can’t really target belly fat specifically, but reducing your overall body fat can lead to a reduction in abdominal fat. Some of these steps also target factors that increase belly fat specifically.

Here’s more on how to do each one of those steps.

Get Enough Sleep for You 

Getting enough sleep for you can help you avoid weight gain and belly fat gain, and it’ll help you feel more energetic and motivated, which can make other weight loss efforts (like exercising and sticking with a healthy diet) easier. 

Want proof? One study found switching from sleeping six hours or less a night to sleeping seven to eight hours a night would lead to gaining almost 1 square inch less visceral fat (fat found deep within your abdomen). This was after BMI, exercise, and calorie intake were taken into account, too. 

Getting enough sleep supports weight and belly fat loss by regulating the hormones leptin and ghrelin, which control hunger and satiety. Sleep loss can disrupt the balance of these hormones, reducing leptin levels, which diminishes feelings of fullness, and increasing ghrelin levels, which heightens hunger. This hormonal imbalance can lead to increased appetite and cravings, making it more challenging to lose weight and belly fat.

Sleep loss can also increase cravings for unhealthy foods and the stress hormone cortisol, which can trigger the body into storing fat, especially stomach fat.  

The trick here is getting enough sleep for you

This is known as your sleep need. The RISE app can calculate your individual sleep need, so you know exactly what you should be aiming for each night. 

This number is different for everyone. For example, among 1.95 million RISE users aged 24 and up, we found sleep needs ranged from five hours to 11 hours 30 minutes.

The RISE app can tell you how much sleep you need.
RISE users’ sleep needs.

If you haven’t been meeting your sleep need, you’ll have built up sleep debt. This is the amount of sleep you owe your body. 

The good news about sleep debt is you can catch up on sleep and pay it back to help melt belly fat.

You can do this by: 

  • Taking naps during your natural afternoon dip in energy — RISE can tell you when this is each day 
  • Going to bed a little earlier 
  • Sleeping in a little later
  • Improving your sleep efficiency (how much time you spend in bed actually asleep) with sleep hygiene (more on that below) 

RISE can work out how much sleep debt you have and keep track of it each day. 

RISE app screenshot showing how much sleep debt you have
RISE works out your sleep debt

RISE users on iOS 1.202 and above can view their sleep need here and view their sleep debt here.

Sync Up with Your Circadian Rhythm 

Syncing up with your circadian rhythm is a trick to help you lose stubborn belly fat that’s often overlooked. 

Your circadian rhythm is your roughly 24-hour body clock. Sleeping and eating at the wrong times for your circadian rhythm can impair glucose tolerance and cause weight gain, belly fat gain, obesity, and abdominal obesity (obesity around the middle of the body).

Getting in sync with your circadian rhythm, on the other hand, can help you avoid weight gain and make weight loss easier, including around the belly area. 

Here’s what to do: 

  • Keep a consistent sleep schedule: Go to bed and wake up at the same times each day, even on weekends. 
  • Go to bed at the right time for you: Depending on your circadian rhythm, there’s a time of night when you’ll find it much easier to fall asleep. RISE can tell you when this is. 
  • Eat meals at consistent times each day: Eating, especially at consistent times, acts as a Zeitgeber—a German term meaning "time giver.” Alongside light and temperature, regular mealtimes help synchronize your internal circadian clocks with the external environment, making it easier for you to keep a consistent sleep schedule. 
  • Eat during daytime hours and not too late in the day so as to not disrupt your sleep or circadian rhythm (more on this soon).

RISE can predict the timing of your circadian rhythm each day. You’ll see when your body wants to wake up, wind down for bed, go to sleep, and when you should finish up dinner each day. Sync up with these times for the best weight loss results. 

RISE users on iOS 1.202 and above can see their circadian rhythm on the Energy screen here.  

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Maintain Good Sleep Hygiene

Restless sleep can lead to obesity and low sleep efficiency (when you spend a lot of time awake in bed) can lead to belly fat. This is where sleep hygiene can help. 

Sleep hygiene are the healthy behaviors you can do throughout the day and night to help you sleep better. They’ll help you fall asleep faster and reduce nighttime awakenings, improving sleep efficiency. Good sleep hygiene will also help you keep sleep debt low and stay in sync with your circadian rhythm. And many of these behaviors also help shrink belly fat as well as improve your sleep.

Here’s what to do: 

  • Get natural light in the mornings and during the day: This will regulate your circadian rhythm, making sure you feel sleepy come bedtime. Aim for at least 10 minutes of light as soon as possible after waking up, or 15 to 20 minutes if it's overcast or you’re getting light through a window. The more bright light you get during the day, the less disruptive light will be to your sleep in the evening. 
  • Avoid sleep disruptors: Steer clear of caffeine, alcohol, exercise, and large meals too late in the day.
  • Make evenings dark: Put on blue-light blocking glasses and dim the lights about 90 minutes before bed. 
  • Wind down before bed: Take time to do relaxing activities like reading, journaling, and yoga before bed.
  • Keep your bedroom dark, cool, and quiet: Use blackout curtains, an eye mask, and ear plugs

The RISE app can tell you the right time to do 20+ sleep hygiene habits based on your circadian rhythm each day. Doing them at the right time for you will make each habit even more effective. 

RISE app screenshot showing sleep hygiene habit reminders
RISE can guide you through 20+ sleep hygiene habits.

RISE users on iOS 1.202 and above can set up their 20+ in-app habit notifications here

Eat a Balanced Diet

To lose belly fat, you’ll want to eat fewer calories than you burn. 

To do this, opt for healthy foods like:

  • Fruits
  • Veggies
  • Complex carbs like oatmeal, brown rice, sweet potatoes, and quinoa 
  • Lean proteins like chicken, turkey, fish, and tofu 
  • Healthy fats like olive oil, nuts, seeds, and avocado 

In particular, up your intake of fiber. This can help you stay fuller for longer, regulate your blood sugar and digestion, and improve your sleep. 

You can find fiber in foods like: 

  • Veggies
  • Oats
  • Lentils
  • Beans
  • Chickpeas 

When it comes to cutting down, cut down on:

  • Sugar
  • Processed foods
  • Simple carbohydrates like white rice, white pasta, and baked goods 
  • Trans fats, which are found in baked goods and fried foods. 

The right foods can also help promote sleep. We dive into what to eat for better sleep here. 

Heads-up: Things like dietary supplements, detox green teas, and fat-burner drinks all promise to help you lose weight fast and get you a flat belly, but there are safer and more natural ways to lose belly fat

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Don’t Eat Too Late in the Day 

To lose fat, you need to think about when you eat, not just what you eat. 

Eating too close to bedtime can disrupt your circadian rhythm and cause digestive issues like bloating and constipation, which can further disrupt your sleep. This can cause weight gain and belly fat gain in particular. 

But people who eat late are also more likely to eat unhealthy foods and your body can’t digest calories as well in the evening as it can during the day.

For the best sleep, avoid eating at least two to three hours before bed. 

Finishing dinner even earlier than this to have a longer period of time between dinner and the next day’s breakfast can promote weight loss, too. 

This is a form of intermittent fasting, or time-restricted eating, which is when you reduce the window of time in which you eat your meals during the day. 

This can help with weight loss as spreading your meals over a large period of the day keeps your body in fat-making mode, instead of fat-burning mode. 

We’ve covered more on what time to stop eating to lose weight here, including tips on how to stop eating late at night and more into how intermittent fasting affects weight loss here.

RISE app screenshot to set reminder for when to have your last big meal
The RISE app can tell you when to stop eating each day.

RISE users on iOS 1.202 and above can set up their avoid late meals reminder here.

Exercise 

If you want to burn belly fat specifically, it can be tempting to try to “spot reduce” fat loss in this area by doing a lot of crunches or ab workouts. But that’s not the way fat loss works. 

But exercise can help you lose overall body fat, which can help you lose belly fat, too. 

Even low-intensity exercise like walking has been shown to help reduce both overall body fat and belly fat specifically. 

Plus, exercise promotes sleep, which will help with belly fat loss. 

Just be sure to avoid intense exercise within an hour of bedtime as this could make it harder to drift off. 

Cut Down on Alcohol 

Alcohol is high in calories and sugar, and it’s linked to weight gain, obesity, and abdominal obesity. Plus, when you drink a lot, you’re more likely to opt for unhealthy foods, adding to belly fat gain. 

To flatten your belly, cut down on the amount of alcohol you drink. You can swap your favorite alcoholic drinks for non-alcoholic versions, reduce your serving sizes, and cut down on the amount of nights you drink each week. 

Cutting down on alcohol will also improve your sleep, boosting your weight loss efforts even more. 

For the best sleep, avoid alcohol at least three to four hours before bed. 

RISE can tell you the best time to have your last alcoholic drink.

RISE users on iOS 1.202 and above can set up their avoid late alcohol reminder here.

Reduce Stress 

Stress triggers the hormone cortisol, which, in high levels, can cause your body to store more fat around the belly area. 

High cortisol can also mess with your hunger hormones, making it more likely you’ll overeat and it can keep you up at night, making it even more likely you’ll gain belly fat that’s hard to lose. 

To lower stress, try:

  • Spending time with loved ones (believe it or not, social routines and interactions can also act as Zeitgebers, so spending regular time with others can also help you keep a consistent sleep schedule and as well as help regulate your mood)
  • Exercising 
  • Journaling 
  • Meditating or doing breathing exercises 
  • Taking time to unwind before bed with relaxing activities like yoga or reading

Learn more about how to stop cortisol weight gain here.

RISE can walk you through relaxation and breathing exercises like diaphragmatic breathing and progressive muscle relaxation.

RISE app screenshot showing relaxation session reminder settings
The RISE app can guide you through relaxation exercises to lower stress.

Caption: The RISE app can guide you through relaxation exercises to lower stress. 

RISE users on iOS 1.202 and above can go right to their relaxation audio guide homepage and get started here.

Heads-up: If you’re trying to lose weight, you might be taking weight loss drugs like Ozempic or Zepbound. These drugs can help you lose weight, but they can also impact your sleep. Learn why this happens with Ozempic here and Zepbound here.

What Causes Belly Fat?

Belly fat can be caused by not getting enough sleep, not being in sync with your circadian rhythm, a poor diet, eating too late in the day, lack of exercise, stress, alcohol, or menopause.

When it comes to your sleep and circadian rhythm, research shows: 

  • Not getting enough sleep can lead to belly fat and weight gain 
  • Not getting enough sleep can lead to insulin resistance, which causes belly fat 
  • Disturbed sleep can lead to belly fat 
  • Eating and sleeping out of sync with your circadian rhythm can lead to weight gain and more fat mass 
  • Sleep disorders like sleep apnea (when your breathing is cut off multiple times each night, often waking you up) can lead to weight gain. 

Does Sleep Help You Lose Weight? 

Yes, sleep can help you lose weight by regulating appetite-controlling hormones, reducing cravings and the likelihood of overeating, and giving you the energy you need to be active, do sleep-promoting behaviors and make good food choices. Getting enough sleep for you, getting undisturbed restful sleep, and getting this sleep in sync with your circadian rhythm can stop you from gaining weight and make losing it much easier. That goes for weight in general and weight around the belly area. 

We’ve covered more on the connection between sleep and weight loss here.

Banish Belly Fat with a Good Night’s Sleep 

Losing belly fat isn’t easy, especially as you can’t spot reduce it, so you’ll need to focus on losing fat overall. But there are some things beyond diet and exercise that you may be overlooking when it comes to fat loss.

Keeping your sleep debt low and syncing up with your circadian rhythm can stop more belly fat from forming and help you lose existing body fat. It can also make all your other weight loss efforts — like working out and eating healthfully — easier.

The RISE app can help.

RISE keeps track of sleep debt as you pay it back and predicts your circadian rhythm each day so you can sync up with it. It also tells you the best time to do 20+ sleep hygiene habits, which will help you sleep easier and longer each night at the right time for you. 

RISE users say they noticed the difference in their sleep and their health: 

“After figuring out how I should sleep with this app, I felt a lot better and my health is better too!” Read the review

And it doesn’t take long — 80% of RISE users get more sleep within five days.

Summary FAQs

How can I lose belly fat overnight without exercise? 

You can lose belly fat overnight without exercise by making sure you’re getting enough sleep for you and getting this sleep in sync with your circadian rhythm, or body clock. Eating a balanced diet, avoiding eating too late in the day, cutting down on alcohol, and reducing your stress levels will also help.

How do you get a flat stomach overnight? 

You can't get a flat stomach overnight but by making sure you’re getting enough sleep for you and getting this sleep in sync with your circadian rhythm, or body clock, you'll get a flatter stomach over time.

How can I lose belly fat immediately?

Losing belly fat takes time, especially losing fat from the belly. But you can speed up the process by making sure you’re getting enough sleep for you and getting this sleep in sync with your circadian rhythm.

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