Can too much or too little sleep make you fat? Yes. Here's how, and what you can do about it.

Updated: Apr 20

In this issue:

  • Why sleep is important

  • What can interfere with our sleep

  • What can happen to our weight when we don't get enough sleep

  • What can happen to our weight when we get too much sleep

  • Practical things that we can do to improve our sleep quality and quantity

  • Practical things that we can do to manage our food intake if we suffer from lack of sleep

There is a lot of evidence to suggest a strong relationship between the amount and quality of our sleep, and our weight, both in terms of cause and effect, and possibly other influences which affect both sleep and weight.

Why is sleep important?

We know that getting an optimum amount of sleep can support our health, in so many ways, and generally we feel better and can function better when we have had the right amount of sleep. When we haven't had enough we can feel tired, grumpy and irritated, and it's harder to function generally, and can make us feel unwell. There is a reason why sleep deprivation has been used as a form of torture through the ages!

The generally recommended amount of sleep for adults is 8 hours per night, but it is a very individual thing.

The body operates a 24-hour sleep-wake cycle during which it completes various important functions that run in the background. We need sufficient sleep in order to:

  • make connections in our brains

  • repair body and brain tissues

  • regulate hormones

  • regulate appetite

  • regulate body composition

  • restore body and brain chemistry

  • strengthen our immune system

  • organise our memories

  • remove waste products

Various factors and especially the amount of light, influence our body clocks. When everything is running smoothly we get regular, good quality sleep and the functions and processes which are supposed to happen when we sleep can take place effectively.

However, when things interfere with our body clocks, and we are unable to either sleep the right amount or have good quality sleep, these functions and processes cannot take place efficiently, and we can develop a vicious circle of problems.

As well as affecting how we feel, an ongoing lack of sleep is linked to many health problems, such as type 2 diabetes, depression, strokes, heart attacks and many other conditions.

What affects how much sleep we get?

Various things can affect our sleep. Here are some common ones:

  • Stress, anxiety and depression

  • Bad dreams

  • Eating late

  • Going to bed late

  • Screen time

  • Working late

  • Noise

  • Temperature

  • Shift work

  • Jet lag

  • Children waking in the night

  • Pets needing comfort or letting in the garden

  • Getting over tired

  • Napping too long in the day

  • Medical conditions

  • Pain - either short or long term

  • Medications

  • Alcohol

And of course, being overweight can affect our sleep quality... most notably due to snoring and sleep apnoea (when our breathing stops and starts while we sleep), further compounding the problem.

Addressing as much as we can from this list can help.

What can happen to our weight when we don't get enough sleep?

Following restorative sleep - the right kind of sleep - the body is able to properly regulate hormone activity including:

  • insulin, which regulates the levels of glucose in our blood

  • ghrelin which stimulates appetite and promotes fat storage, and

  • leptin, which signals when we are have eaten enough.

When we haven't had enough sleep, or it's not of good quality, the levels of these hormones can be affected, and drive various changes inside our bodies, and also in our behaviour, which further compounds the problem. For example, ghrelin levels can rise, and leptin levels can fall, leading us to feel more hungry, even after just one night of reduced sleep. Furthermore, studies have shown that lack of sleep increases insulin resistance, meaning we are more likely to store fat. Yet we still feel hungry because our muscles need the fuel but are not getting so much of it. We are also driven to eat higher calorie foods, and managing cravings can be more difficult when we are feeling tired and grumpy and more likely to emotionally eat. The combination of these factors, amongst others, does not bode well for our waistlines!

There are very complex systems at work which I have greatly simplified, and I am not going to go into lots of details here but there are articles at the end which you can read if you want to understand this further.

So, given what I have just explained, it is very common to experience more hunger when we haven't had enough sleep. Not only that, we also tend to crave more high calorie, processed foods. And because we're tired, we find it harder to resist them, and we care less about the consequences. Then we eat them, which makes us want more of them. This can then set up a pattern of behaviour because the food and drink that we choose, and when we eat and drink them, especially if we snack on them in the evening, can then affect the quality of our sleep the next night, and so on. And as we feel tired, we're less inclined to take exercise... and so it goes on...and if our weight increases, that will further increase the likelihood of poor quality sleep.

This combination of factors is likely to lead to continued weight gain, so it is vital that we find ways to break this cycle.

What can happen to our weight when we get too much sleep?

It is inevitable that the more time we spend asleep, not moving very much, the less energy we will burn in a 24 hour period, meaning we are more at risk of eating more than we are burning.

Furthermore, the less we do, the less we feel like doing, as our motivation is reduced and we feel sluggish and tired and reluctant to do exercise. We might also develop aches and pains from lack of activity, which is inclined to make us even less active. Our mood is also likely to be affected, and emotional eating can result.

So another pattern develops as we end up sleeping more, and are at risk of weight gain. Again it is key to find ways to break this cycle.

What you can do to improve your sleep time and quality

Ideally we need to tackle the causes of lack of sleep. However, there are also practical things we can do to address our sleep time and quality.

Things that support the body's natural sleep -wake cycle include :

  • getting outside to get exposure to sunlight - don't stay cooped up indoors all day, try to get outside as much as your schedule will allow

  • getting into a routine with going to bed and getting up times, even at the weekend

  • taking regular exercise

  • spending time relaxing in the evening

  • avoiding bright lights in the evening

  • avoiding looking at your phone computer screen in the couple of hours leading up to bed time

  • avoiding going to sleep during the day, or keeping it to a minimum, and at regular times

Thing to avoid that can interfere with your sleep include:

  • not eating a large meal in the evening

  • not eating before bed time - if you are hungry stick to something really small and light and review your meal times to try to avoid late night hunger

  • not drinking lots of fluids before bed time, so you are less likely to need the toilet during the night

  • avoiding caffeinated drinks as much as possible and especially in the afternoon and evening

  • not drinking lots of alcohol, as while it can help us go to sleep, the length and quality of our sleep can be affected

Things that are known to help with sleep quality include:

  • lavender pillow spray

  • a sleep mask

  • a comfortable and supportive pillow and mattress that are right for your body

  • an air purifier

  • ear plugs

  • an alarm clock with a light that mimics the sunrise - known as SAD lights. See link at the foot of this page.

  • A sleep tracker, to monitor the length and quality of your sleep.


If you are on prescribed medication or have a medical condition or are in pain, seek a review with your doctor if it's affecting your sleep.

Also you may find it helpful to seek advice from a sleep specialist if you are suffering from a chronic lack of sleep and have already tried to address the root causes and symptoms without success.

What we can do to manage our food intake if we suffer from lack of sleep

The good news is that even if we are unable to improve our sleep very much, perhaps because the causes are beyond our control, there are still things we can do to help manage our eating while dealing with the effects of lack of sleep, which as well as helping manage our weight, may in turn help to reduce or manage the factors that are affecting our sleep.

Like with many things, it comes down to being aware of our triggers and making more conscious choices, breaking unhelpful patterns of behaviour, and developing better habits.

Some of these may be useful to you.

Recognise what's driving your behaviour

Like with may things, paying attention to how we are feeling, and understanding what's going on, can be a huge step forward in managing the problem and helping us to make better decisions.

Recognise you have a choice

While we might not be able to avoid how we are feeling in the moment as a result of the lack of sleep, we do have a choice about how we respond to it, and are not powerless to do anything about it. Just remembering this can be hugely helpful.

Plan ahead

Knowing that hunger and cravings for sugary or salty foods, or stodgy carbs are likely to be the biggest issues, the key thing will be to make it as easy as possible to make the best choices in the moment. So that means planning ahead in terms of what and when we will eat.

Eat good quality foods

So we need to make sure we have easy access to lots of tasty, low calorie but highly nutritious, unprocessed foods, containing all the food groups, that are quick to prepare and easy to eat, so we can choose them instead of the sugary, highly processed foods when we are feeling urges that we are struggling to stay on top of because we are so tired. This will help to regulate blood sugar levels and reduce hunger and cravings.

Find good, quick and easy recipes

If you enjoy cooking, then spend some time looking for recipes. Pinch of Nom is very popular with people who are looking for interesting, tasty, healthy recipes.

Choose foods that you like

It is so important when planning our good quality nutritious food, to put the effort into finding and choosing things that we like, and have them ready in advance, otherwise in the moment we will not care and just go for the sugary processed foods.

Limit access to sugary foods

It is vital to limit your access to those sugary, processed foods. Either don't have them in the house, don't go near where they are sold, avoid things that are likely to trigger you into wanting them or keep them completely out of sight and difficult to access, giving you more time to talk yourself out of eating them.

Drink lots of water, not caffeine

While you might be tempted to drink lots of caffeine to keep you awake, it is not going to do much to help your sleep the following night, and will only serve to perpetuate the problem. Not only is water what we are designed to drink, it will help you to manage the cravings.

Work on your mindset

Remind yourself why it's important not to give in to the temptations to eat the foods that you know are not going to serve you in the long run. Keep reminders around you, and develop mantras that can help you in the moments when you are feeling vulnerable.

For more on what you can do, check out my articles on:

Ironically I have been writing this while suffering from the effects of insufficient sleep so I can fully relate to a lot of the things that I'm talking about here right now.

I'm feeling more hungry than normal despite eating good quality food and I'm craving carbohydrates. I'm also feeling less bothered about the consequences of making poor choices so I'm having to work hard on myself to make sure that I don't make those poor choices.

It's quite an effort today.

Knowing that this is most likely due to not having enough sleep reminds me that I still have a choice about how I respond. And so do you.

If you found this helpful why not check out my e-books

Eating Less - simple, practical ways to eat less without going on a diet. Just £5.99

Preparing for Successful Weight Loss - helping you to put all the right things in place to support your weight loss journey and keep your weight off for good. Just £9.97

Further reading

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