SIMPLE’s comprehensive guide on sleep and weight loss

Written by Melissa Renae

Medically reviewed by Louise Bula, RD

Published on October 27, 2023 | Updated on March 28, 2024

Sometimes weight loss success seems to be as unique as a snowflake or a fingerprint. What your cousin’s best friend did or what that social media influencer swears by hasn’t worked for you so far. Truth be told, there’s almost always more to the weight loss story than the basic idea of calories in vs calories out. It may take reducing or managing stress, adding or increasing physical activity, trying intermittent fasting … even medication or surgery for some. 

We know that what, when, and how much you eat, your metabolism, and how much you move all play a role in losing weight. Trying to focus on all of those things and everything else you need to do in a day can have you bailing on one thing that might just be your missing link. 

Now we’ve got you wondering, “Hold up, what missing link? Wait, could it be … does sleep affect weight loss?” Yup — you guessed it! 

It was probably an easy guess, because it’s the one mark you know you haven’t been hitting. Sleep — or the lack of it — can hinder all your efforts. Sleep quality and duration have a major impact on your health, affecting things like blood pressure, blood sugar, and, yes, weight management![1–3] 

Sleep and weight loss go hand in hand just as much as nutrition and weight loss. Who’d have thought getting those 8 hours of sleep might be better for a successful weight loss journey [4] than cutting it short to get that pre-dawn workout in?

Let’s find out more about just how sleep affects weight loss. 

How does sleep affect weight loss? 

You might be asking yourself, “But SIMPLE, how does sleeping help you lose weight?” Let us fill you in. 

When you’re asleep — especially if it’s deep sleep — you may think you’re just resting. But for your body, it’s GO time. 

Your body needs those recommended 7–8 hrs of rest to recover from everything you do in a day.[6] While you snooze, your body gets busy repairing cells and tissues, clearing out toxins and impurities, and burning calories. 

Yes, you read that right, we burn calories while we sleep! On average, during a 7-8 hour sleep, we can burn about 300-600 calories [7] — equivalent to a 30-minute HIIT workout!

Let’s look at some other ways that sleep can help your weight loss efforts.

Sleep can decrease your appetite

Did you know that your hunger and fullness responses are triggered by hormones? Leptin is the hormone that triggers your brain to say you’re full. Ghrelin is the hormone that tells your brain it’s time to eat. When you don’t get enough sleep, your leptin levels will decrease while your ghrelin levels can increase and trigger the munchies [8], and that can make sticking with your fast much harder. Whether or not fasting is your method for trying to promote weight loss, increased caloric intake is most likely going to be counterproductive. 

Sleep can upgrade your metabolism 

The majority of the processes that support your body’s metabolism happen when you’re asleep. Remember that overnight calorie burn we talked about? That’s because it takes calories to do all that work! 

Proper sleep helps your metabolism to work more efficiently [9], so the energy and nutrients you’ve eaten are used, instead of being stored as fat. 

Sleep can alleviate stress 

Think of a grumpy toddler who missed nap time. Now put that inability to cope in the body of an adult who has to think, work, and dare I say it … drive in traffic. It’s a stress-fuelled nightmare waiting to happen! 

Often stress triggers cravings for alcohol, sugar, and caffeine to help us cope, and lack of sleep makes those cravings worse.[10] Not only does getting enough sleep make stress easier to cope with, but it makes our appetite easier to manage. It also gives us more energy to be physically active, which also helps lessen our stress. 

Sleep can increase fat burning 

Another reason why sleep is important for weight loss is the role it plays in insulin regulation. Every time you eat, insulin moves glucose from food into cells for energy. Insulin will store excess energy as fat when cells are resistant to it. Weight loss is supported while you’re sleeping because essentially, you’re fasting and your insulin levels can take a break. This allows your body to tap into those fat stores for the energy it needs to get through its nighttime recovery routine. 

Sleep can enhance physical activity

It’s not just what happens at a cellular or metabolic level. It’s also behavioral. Weight loss and sleeping go together so well because sleep also helps us do things like get more physically active. 

Your body recovers during sleep. Energy stores are prepared for the next day. Your muscles and brain repair. When you wake up, you feel refreshed, peppy, and motivated to get moving!

Proper sleep also means proper recovery, which leads to better performance and injury prevention, meaning you can keep exercising and working to improve your health long term. 

It’s a two-way street, too — exercise has been shown to support better quality sleep.[11] Combining good quality sleep and exercise could give you a triple threat in your weight loss arsenal. (If you’re not sure how to best fit in exercise while practicing intermittent fasting, check out our article on exercise and intermittent fasting.)

Wondering whether intermittent fasting is for you? Take our SIMPLE quiz to see how fasting could support your efforts to lose weight. 

Sleep can improve brain responses 

Adequate sleep keeps your mind sharp and better regulates the pleasure centers of the brain. Sleep can help you lose weight by preventing cravings for high-fat and high-sugar foods that the sleep-deprived mind may give you the green light for.[12]

Think of a sleep-deprived brain like a drunk brain. Your inhibitions are lowered and that fast food cheeseburger at midnight tastes much better than it tastes when you eat it sober. 

Risks of sleep deprivation 

Just as quality sleep has benefits, sleep deprivation has risks that highlight the importance of sleep for weight loss. These include:

Increased insulin response 

Leptin and ghrelin are not the only hormones affected by lack of sleep. Sleep deprivation can also trigger insulin release.[2] Short-term inadequate sleep can increase insulin response, leading to insulin resistance by as much as 30%.[2] Insulin resistance means glucose is not getting into the cells for energy and therefore being stored as fat. Increased fat storage can lead to reduced insulin sensitivity and higher blood glucose. Over time, this can lead to type 2 diabetes.[13]

A higher body mass index (BMI)

When you’re sleeping regularly and well, you’re fasting more frequently, so fat stores can be tapped into for energy. However, with shorter and fewer sleep periods, cravings and increased calorie intake are a real possibility, which can lead to weight gain and a higher BMI.[14] Some research has shown that lack of sleep can lead to an increase in food intake and a decrease in the quality of food choices.[15] Over time, this can contribute to an increase in BMI.

A high BMI, especially due to high body fat percentage, is a precursor for metabolic diseases like high blood pressure, type 2 diabetes, and heart disease.[16] Obesity can also lead to sleep disorders, like sleep apnea, further fueling this vicious cycle of poor sleep quality and declining health. 

Poor mental health

Ongoing sleep deprivation [17], whether from lack of sleep quality or sleep duration, can negatively affect mental health.

Lack of sleep has been shown to reduce emotional regulation, (remember that nap-less toddler), increase anxiety and depression symptoms, and reduce cognitive functions such as the ability to focus, comprehend, and remember.[3,18,19] 

From a weight loss perspective, finding it hard to cope with stress often leads to increased cravings (triggered by elevated cortisol levels [20]) and the need for comfort. Comfort food is called comfort food for a reason — it satisfies cravings for high-calorie foods and drinks and “takes the edge off.” 

Tips on sleeping your way to weight loss

To ensure good quality sleep, work on your sleep hygiene and put a plan in place to take your sleep from poor to rich. Try these tips to step up your nightly routine.

Avoid large meals, alcohol, caffeine, and cigarettes before bed

Decreasing the amount of calories and sugar you eat before bed can help you sleep better.[21] A great way to do this is to begin your fasting window a few hours before you hit the sack. 

If you haven’t started your intermittent fasting journey yet, read intermittent fasting for beginners for a strong kick-off, then take our SIMPLE quiz to take advantage of all the trackers, articles, and features in the app that can make fasting a breeze. Losing weight and building great health habits is so much easier with the right support.   

Develop a relaxing nighttime routine

Your mind and body need time to calm down from the day. Try soothing activities like a warm shower or bath, stretching, journaling, or reading about an hour before bedtime. 

Check the life expectancy on your mattress and pillows

If your bed is lumpy, bumpy, and uncomfortable — or you roll straight to the middle as soon as you lay down — it’s time to go mattress shopping! It’s recommended you replace your mattress every 9-10 years. Your pillows may also be due for a change. 

Create a quality sleep environment

Cool, quiet, and dark is the recipe for a perfect night’s sleep. 

• Cool: Temperatures in the 60’s are ideal, but if you don’t want to drop your thermostat that low, a fan can also help achieve cooler temperatures. 
• Dark: Melatonin, your body’s natural sleep hormone, is triggered by darkness. If you can, limit your electronic time in the evening. That means switching off the TV, computers, phones, and tablets, and dimming the lights about 30–60 minutes before bed. Turn off all of the lights, or use a sleep mask to minimize the light. If the sun rises before you get to your 8-hour mark, blackout curtains can be key to finishing up your rest uninterrupted. 
• Quiet: If you live in a noisy neighborhood, or sleep with a noisy partner or pet, try earplugs to minimize the noise. 

Adhere to a schedule (even on weekends)

Find your sweet spot (7-8 hours is ideal, but we’re all different) and stick to it — even on the weekends. Your internal body clock will get used to sleeping and waking up at the same time. Developing and maintaining consistent sleep habits will make it easier to fall asleep and stay asleep.

Keeping your bedtime schedule on the weekends may not feel like the most rock and roll thing to do, but your body — and your weight loss goals — will love you for it. 

SIMPLE’s expert opinion and final thoughts 

Trying to lose weight can be affected by so many different factors, and now you know why sleep is important for weight loss. Sleep affects the hormonal and metabolic processes that regulate our appetite, our moods, our energy levels, and our impulse control.[4] 

To lose weight successfully, we need to pay attention to the things that influence both how much energy we take in and how we use that energy, like:

• exercise to burn energy and increase metabolism-revving muscle mass;
• an eating pattern like intermittent fasting that does not slow metabolism, but helps to maintain it; 
• eating health-promoting, appetite-controlling foods during your eating windows; and 
• high-quality, plentiful sleep.

Sleep is important for weight loss because it is key to all these other components of weight loss working efficiently. If you’ve been trying everything but not seeing the progress you hoped for, take a look at your sleep patterns.

If you haven’t yet tried all the things, but you’d like to, take our SIMPLE quiz and start your weight loss journey with us. We know it’s not for everyone. If you fit into any of these categories, we recommend you skip fasting as an option. 

• are pregnant, breastfeeding, or trying to conceive
• have type 1 diabetes
• are on prescription medications 
• are under 18 years old, or 80 years old or more
• are extremely active
• have a body mass index (BMI) < 18.5
• have an eating disorder or a history of one (or are at risk of developing one)

But, if you don’t, we’ll be happy to help you whip your eating and exercise habits into shape, support you to try fasting safely and effectively, and teach you all kinds of useful things that’ll make you think, “Ohhhh, that’s why I’ve been struggling with xyz!”

Frequently Asked Questions about sleep and weight loss

How many hours should I sleep to lose weight? 

How many hours you should sleep to lose weight, according to research, is 7-8 hours.[22] Adults need enough sleep to support the metabolic processes that support weight loss. Even one day of sleep deprivation (less than 6 hours) can result in changes in glucose tolerance and insulin sensitivity. [2] That said, we’re all unique, so your perfect amount might be more or less. 

Does excess sleep cause weight gain? 

Excess sleep can cause weight gain [23] — oversleeping can lead to health risks and body clock disruption just like undersleeping. Regularly needing more than 9 hours of sleep could be a sign of a sleep disorder like sleep apnea or restless leg syndrome, or a mental health condition like depression.[24] It would be a good idea to seek medical advice. 

Can you lose weight by napping? 

While naps are wonderful, they’re too short to help with weight loss. Shorter naps (10-20 minutes) can temporarily fill in the gaps for sleep deprivation and may be a healthier, more weight-loss-supporting option to get through the day than caffeine or sugar. Longer naps can disrupt your sleep patterns and hinder a good night’s sleep.[25] 

Is 10 PM to 4 AM enough sleep? 

10 PM to 4 AM is only 6 hours and therefore probably not enough sleep for most people. Ideally, adults need 7-8 hours of sleep for full mental and physical health, and having a pattern of shortened sleep over time can lead to health problems. If you’re consistently only getting 6 hours of sleep, review our tips on improving sleep quality and see if you can make any changes to increase your sleep duration (pssst, blackout curtains for the win!).

Does lack of sleep cause aging? 

Yes, lack of sleep can cause aging.[26] During sleep, dead and damaged cell parts are discarded or recycled. Without time for proper recovery, cellular waste can accumulate and disease processes can begin. Sleep deprivation can also increase the risk of cognitive impairment.[19]

Written by Melissa Renae

Medically reviewed by Louise Bula, RD

Published on | Updated on March 28, 2024