The relationship between sleep and weight

Reviewed by our clinical team

As many as one in three people have problems sleeping, and as many as two thirds of UK adults are either overweight or obese, making them two big health issues. If you’re trying to maintain a healthy weight there’s a lot of different things you need to think about, from eating a healthy, balanced diet, to staying active and drinking enough water. But did you know that sleep can also be an important factor in looking after your weight too? And on the flipside, your weight can impact how well you sleep?

In this article we’ll take a look at why sleep is important, the relationship between how well you’re sleeping and how you can try to get a better quality of sleep. 

Why is sleep important?

Sleep is so important because it helps your body and mind rest, recuperate and recover from the day. While you’re sleeping, the body carries out maintenance on tissues, muscles, bones and blood vessels. 

Sleep also helps your mind process the day’s thought and experiences, this helps you create memories and hold onto information. Not getting enough sleep can impact how well you concentrate, and problem solve, this can be particularly challenging for children at school. 

Bad quality of sleep, or not getting enough, can impact your immune system and increase your risk of certain conditions like diabetes, heart disease and high blood pressure. As well as physical conditions, poor sleep can affect mood and feelings of stress. A lack of sleep can sometimes increase your risk of anxiety and depression, as well as other mental health conditions. 

Can bad sleep cause weight gain? 

For some people, not getting enough sleep can lead to weight gain. There’s evidence to suggest that regularly getting less than six hours sleep is linked to having a higher BMI (body mass index). And actually, even five days of little sleep can cause weight gain.

Sleep plays an important role in regulating hormones, including those that control your hunger and appetite. By not getting enough sleep you might experience an imbalance in these hormones, leading to you feeling hungrier and eating more. This is why when you’re tired your body is more likely to crave sugary, high-fat foods to provide quick energy. Eating more and eating lots of these types of foods can cause weight gain.

Sleep when you’re trying to lose weight 

There is a lot of evidence to suggest that poor sleep can impede your chances of losing weight. One study found that over 14-day period of a restricted calorie diet, people who got eight and a half hours sleep lost more weight than those who got five and half hours.

Another study found that after an eight-week period of dieting (participants ate just 800 calories a day), people on average lost 12% of their body weight. The weight of the participants was then tracked over the next year, and it was found that those who slept less than six hours a night or had poor sleep quality increased their BMIs more than those who had better sleep. We can’t say for sure that the weight gain is related to sleep, but it shows that the two are linked.

Can bad sleep cause weight loss? 

If you’re awake lots of the night, and you’re not eating enough in the day, there is a chance a lack of sleep could lead to weight loss. But there might be other factors which are disrupting your sleep pattern and appetite, for example stress or anxiety. Both stress and anxiety can impact quality of sleep and how hungry you feel, with lots of people sleeping less and losing their appetites all together.

Oftentimes, this change is only temporary. Your weight may return to normal once the stressor has passed. 

Can being overweight impact your sleep? 

There are lots of things that can impact your sleep. And there is some evidence that being overweight or obese can increase your risk of certain conditions which might impact your sleep.

Snoring 

People who are overweight tend to be more likely to snore. While snoring might be more annoying for the people around you than for you, it can actually impact your quality of sleep. Sometimes you might not even realise that snoring is affecting you, but if you’re feeling tired during the day, it might well be.

For lots of people who snore, losing weight will help them snore less.

Sleep apnoea 

If you’re overweight or obese you’re at risk of a condition called sleep apnoea or obstructive sleep apnoea syndrome (OSAS). If you have sleep apnoea your breathing will stop for 10 seconds or at least 5 times per hour (on average) throughout your sleep period. Generally, your breathing stops, then you’ll snore or snort, and your breathing comes back. Some people even sound like they’re choking.

People with sleep apnoea will wake up multiple times in the night, but they might not even realise. This disturbed sleep will make you feel tired during the day. You might also have headaches, mood swings and find it hard to focus.

Sleep apnoea is most common in middle-aged men who are overweight. It can be dangerous as if left untreated it can lead to an increased risk of high blood pressure, which in turn can increase your risk of heart problems and strokes. Some people with sleep apnoea are also at higher risk of type 2 diabetes.

There are lots of treatments available for sleep apnoea, but if you’re diagnosed, you’ll be advised to lose weight if you’re overweight.

How to get better sleep 

‘Sleep hygiene’ is the term we use to describe all the things we can do to ensure we get a better night’s sleep. While losing weight, if you need to, isn’t exactly sleep hygiene, it could help you get a better night’s sleep, and keep the weight off in the long run. Outside of losing weight, here are some other top tips for getting better sleep:

• Create a routine and stick to it – try to wake up, get ready for bed and go to sleep at similar times each day 
• Exercise during the day – this will help you feel more tired when it comes to going to sleep 
• Don’t exercise too close to bedtime – this can make it hard to wind down 
• Avoid caffeine, alcohol or a big meal close to bedtime – this will make it hard to get into a deep sleep 
• Try and sleep in a dark, cool and quiet space – this works for most people, but you might find that instead of the quiet, something like white noise helps you drift off 
• Avoid using your phone or screens just before going to sleep 
• Leave your phone on silent or out of the room entirely, if possible 
• If worries are keeping you up at night, what could you do to tackle these in the day? Could you speak to someone or talk to your GP to get some help? 

If you do find that you’re lying awake for long periods of the night, you might find that getting up and doing something might help. You could get up and read a book, listen to a podcast or calming music and go back to bed when you feel like you might be able to fall asleep. 

References 

https://patient.info/mental-health/insomnia-poor-sleep
https://researchbriefings.files.parliament.uk/documents/SN03336/SN03336.pdf
https://www.mindwell-leeds.org.uk/myself/exploring-your-mental-health/sleep/why-is-a-good-nights-sleep-important/
https://www.theguardian.com/society/2022/may/04/poor-sleep-may-hinder-attempts-to-maintain-weight-loss-study-finds
https://easo.org/poor-sleep-may-undermine-peoples-attempts-to-keep-weight-off/
https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress-symptoms/art-20050987
https://patient.info/mental-health/insomnia-poor-sleep/snoring
https://patient.info/signs-symptoms/tiredness-fatigue/obstructive-sleep-apnoea-syndrome
https://www.nhs.uk/conditions/sleep-apnoea/
https://royalpapworth.nhs.uk/our-services/respiratory-services/rssc/patient-information/sleep-hygiene
https://www.nhs.uk/every-mind-matters/coronavirus/how-to-fall-asleep-faster-and-sleep-better/