Sleep is a periodic state of physiological rest during which consciousness is suspended and metabolic rate is decreased. It’s the time we take to repair our bodies and provides us with energy for the next day. When we think of the benefits of sleep, we think about feeling physically awake and ready to take on the day. It’s not often we think about how it can impact what we chose to eat too.
Ever felt hungrier after a bad night’s sleep? Or ‘crave’ more sugar and high calorie foods? Keep reading to find out why this might be.
How long should we sleep for?
There is no correct amount of sleep that everybody MUST have. The magical 6-9 hours per night is advised as an average amount to aim for (1,2). But sleep is a natural process that is not directly under our control. Of course, we can determine when we chose to go to bed and set our alarm/get out of bed, but our bodies will take what they need and in the short term adjust to make sure we stay healthy. Research suggests worrying about sleep and thinking we are not good sleepers makes the quality and quantity of sleep worse (2). Ultimately everyone is different, and we will all require slightly different amounts of sleep.
Is sleep duration related to diet?
Our diet and sleep are both linked. This is not a causal relationship meaning one does not directly affect the other, as we do not have evidence for this. But we do know people that sleep for less time tend to consume higher energy foods (3). People with less sleep tend to choose foods with higher fat content, have an irregular eating pattern and consume insufficient quantities of vegetables (3). The Mediterranean diet has also been associated with better sleep hygiene (the quality of our sleep) and lower risk of insomnia symptoms (4,5,6). We also know sleeping for a shorter duration of time results in increased likelihood of skipping physical activity and exercise in the following days/weeks. Which makes sense as sleep plays an important role in our physical health giving our bodies time to rest and repair. Limiting physical activity can lead to lower energy and poor mood which can impact the quality of our sleep, creating a spiral effect.
Sleep and Hormones
So, what drives these changes in nutritional intake? Changes in our hunger and fullness hormones are assisted with sleep deprivation. Leptin, our satiety hormone, and ghrelin, our hunger hormone, help to control appetite. When we have a lack of sleep or poor quality of sleep, the normal production of these hormones is thrown off and they can get all confused. Research suggests this can happen even after short periods of inadequate sleep (7). Sleep is also known to disrupt concentration, decision-making and mood, which all have an impact on the types of foods we chose to eat day to day.
Can our diet help us sleep better?
While it has not been ultimately determined if sleep affects our diet or diets affect our sleep, there are ways we can encourage and support good sleep hygiene through our diet.
Following a balanced diet including 5 portions of fruit and vegetables, wholegrains, sources of protein including meat, poultry, fish, eggs, dairy, pulses and legumes, healthy fats and foods you enjoy helps to improve mood and energy through the day leading to a good night’s sleep.
Foods which are difficult to digest
Our bodies continue to process foods once we are asleep which can disrupt our sleep. Avoiding foods such as processed meats and fried foods before can help keep your tummy happy during the night.
Keeping hydrated helps to support energy levels through the day and prevents dips in moods and headaches. This helps us to feel calm and relaxed when bedtime comes around.
As many of us know, caffeine is a stimulant. It provides a burst of energy when drank which can help give us energy through the day. However, when this is consumed too close to sleep it can have a detrimental effect. Caffeine can stay in our system for 6 – 12 hours so even an early evening cuppa can disrupt sleep. This is very individual, and some people may feel no effects at all and enjoy a warming tea before bed. Remember caffeine is found in fizzy drinks and chocolate as well as tea and coffee.
Drinking alcohol before sleep can negatively affect sleep quality causing us to wake multiple times in the night. Try to avoid this especially on a regular basis.
Of course, it’s not only nutrition which can affect our sleep. Many factors play a role in sleep quality and duration. These include, but are not limited to, our internal and external body clock, light stimulus, hormones, physical activity, hormones, stress, sleeping environment and smoking. Let’s finish with some quick tips for optimising sleep:
- Avoid eating too close to bedtime
- Limit screen time (of any kind) before sleeping
- Have a calm down hour from your day to focus on yourself and really wind down. Try meditation, slow yoga such as yin, breathing techniques or reading a book
- Stick to a regular wake and sleep cycle, aiming to wake up and go to bed at the same time each day
- Avoid consuming caffeine before bed, unless you know this does not affect your sleep
- Follow a regular exercise routine that makes you feel good and energised, avoid exercising too close to bed