Just how important is a good night's kip when it comes to our waistline?

Emma Brown - Nutritionist | 30 Sep, 2020

We all know that a lack of sleep or a bad night can leave us feeling grumpy and lethargic. But aside from these more obvious issues, a lack of sleep can affect our overall health too. There are many ways in which a bad night's sleep can impact on our health, including affecting our waistline – so I thought I'd do a round up of the ways in which our sleep pattern and weight are linked.

Lack of sleep and weight gain

The big question is does a lack of sleep impact on your waistline? Well in many ways – yes! It's not necessarily the lack of sleep that directly leads to an increase in fat stores in the body, but more about how it impacts on our behaviours and choices throughout the day.


Food choices

It seems that lack of sleep can affect what we choose to eat the following day and how much. In one study, researchers observed the brain activity of healthy volunteers using MRI scanners. They took images of the brain on two occasions – following one good night's sleep (8 hours plus) and one night of total sleep deprivation. During the scan the volunteers were shown pictures of food, and their brain reaction to the pictures recorded.

The researchers made a very interesting discovery. After a night of no sleep, the volunteers showed a high level of activation in the area of the brain involved in the desire to eat, compared to the volunteers who had a good night's sleep. After just one night of sleep deprivation, there was a marked difference in the brain's response to food and appetite, suggesting that continuous poor sleep patterns could influence both the way, and the amount that we eat. Over a longer period this alteration in the brain's handling of appetite signals could mean a huge change in calorie intake resulting in weight gain and the inability to lose weight effectively.

Exercise choices

Lack of sleep has many different effects on the body, not least that it reduces our ability to function properly. It can result in a lack of energy which unsurprisingly affects our activity levels. Research has found that when people have had a bad night's sleep, their energy expenditure the following day is reduced.

Making the decision to hit the gym is tough enough without the added hurdle of tiredness and fatigue getting in the way! So it makes sense that inadequate sleep may lead to less activity.


Shift work and weight

When you work shifts, early starts, late nights or working right through can take a big toll on your body in many different ways. Whether you're a policeman, doctor, nurse or working nights on a production line, the effect of shift work doesn't discriminate. In the short term, working shifts can cause sleep disturbances, fatigue, stress and irritability.

There is also evidence showing that shift workers, particularly those working nights, have a greater tendency to gain weight. Although we don't know precisely why this is, it is probably a combination of eating late in the day, snacking more, having a more sedentary lifestyle with more naps, and feeling less inclined to do exercise when off shift.

It's also possible that hormones play a role as the natural sleep-wake cycle is disrupted. There is some research to suggest that the hormone leptin is lower in people who regularly work shifts. This is the hormone responsible for making us feel full, so lower levels can lead to overeating and weight gain.

Here are some practical tips to help if you are a shift worker:

  1. Prepare your food in advance and take it with you to avoid going to the canteen or vending machine
  2. Try to ensure you still eat 3 square meals a day with healthy snacks in between
  3. It may be hard, but try to squeeze some physical activity into your day where possible – it will really help. A walk outside in the fresh air on your break will help to keep you alert and also burn extra calories.
  4. Keep healthy snacks handy for when hunger strikes – a portion of nuts (weighed), fresh fruit, cereal bars, rice cakes, yogurts are all good choices.

Weight gain and sleep apnoea

sleep apnoea

This is the flip side of the issue. Being overweight can actually affect sleep. Obstructive sleep apnoea is a condition in which breathing is temporarily disrupted for 10 or more seconds at a time.

The reason being overweight increases the risk of developing sleep apnoea is because soft tissue can build up around the throat. When asleep and more relaxed, the soft tissue around the throat can start to obstruct the airway, temporarily stopping breathing.

If you suffer with sleep apnoea and are overweight, it's highly recommended that you lose weight as this can ease the symptoms or even cure the condition in many cases.

What to do?


So it seems clear that getting enough good quality sleep is important in many ways. So how can you make sure you do this? Here are some suggestions:

  1. Most adults need at least 8 hours a night, so get to bed early enough to get in a good 8 hours.
  2. Establishing a routine is important. Aim to eat at a similar time each evening, and go to bed at the same time as this is important in programming your body clock.
  3. Try to do something relaxing before you go to bed – reading, taking a bath, doing yoga or listening to music – whatever works best for you to help you to wind down for a good night of undisturbed rest.
  4. Try to avoid eating a big meal or fatty or spicy foods close to bed time as it will leave you feeling uncomfortable, making it harder to get to sleep.
  5. If you struggle to doze off, avoid watching TV, reading your phone or tablet too close to bed time. Research has shown the bright lights from these screens can make it harder to fall asleep.

Nutritionist Emma Brown (ANutr), MSc Human Nutrition is passionate about how food science applies to the human body, and how the nutrients in what we eat affect us and ultimately have an impact on our health.