BLOG BY Emilia Fish, BSc

Do Our Diets Affect Tiredness and Sleep

Sleep is the time we take to relax and repair our bodies; it is something we all need and gives us energy for the next day1,2. There is no set amount that everyone must have, but it is generally found that adults require six to nine hours of sleep every night3,4.  Not having enough sleep can cause problems for our health5.

What is sleep hygiene?

Sleep hygiene refers to the quality of sleep we get1. It can be objectively measured using slow wave sleep and rapid eye movement6,7.

Several factors which can affect the quality of our sleep include the environment in which we sleep, our emotions such as stress and worry, taking certain medications, age and our diets3,8.

For good sleep hygiene, it is recommended to keep a regular sleep pattern, sleep in a comfortable environment, and incorporate movement into our everyday routines while relaxing in the hours before bed1. Dietary factors which affect our sleep hygiene will be covered throughout this piece.

Sleep hygiene and our health.

Our sleep hygiene is closely related to our health:

• Mental Health. Poor sleep can negatively affect our mental health. The reverse is also true; living with a mental health disorder can negatively affect the quality of our sleep9,10.

• Physical Health. Sleep also plays an important role in our physical health. It is the time our bodies take to rest and repair. Recurring sleep problems are associated with cardiovascular and kidney disease, high blood pressure and diabetes5.

Diet and sleep hygiene.

Our diets are linked to our sleep hygiene. This is not a causal relationship, meaning it has not been determined whether sleep affects our diets or if our diets affect our sleep11.

What research has found is that people who sleep for less time, often consume higher energy diets12, commonly noting that people with less sleep tend to choose foods with higher fat content13,14. Research also finds that the Mediterranean diet has been associated with better sleep hygiene15 and lower risk of insomnia symptoms16.

The general dietary advice to achieve good sleep hygiene is in line with the government’s dietary guidelines for a balanced diet11,17.

How can our diets reduce daily tiredness?

A balanced diet. Following this helps to improve our mood and energy throughout the day, which supports our sleep. It is recommended to18,19:

• Eat at least five portions of fruits and vegetables a day. These contain micronutrients which support our physical and mental well-being.

• Eat some protein including two portions of fish a week. Protein sources contain amino acids which we need to regulate our emotions. They also keep us satiated.

• Eat some unsaturated fats. These contain omega-3 and omega-6’s, which support our mood and physical health.

Think about hydration. Drinking six to eight glasses of water will support our energy levels throughout the day18,19.

Consider the time we eat. To sustain energy levels, it is recommended to eat 3 meals throughout the day at regular times and to ensure we eat breakfast. If you do not like breakfast, maybe try a piece of fruit to help sustain your energy until lunch time18,19.

How can our diets negatively affect our sleep hygiene?

Caffeine. Caffeine is a stimulant. This means that when it is consumed, it provides a quick burst of energy, so can be perfect for during the day, but later in the day, it can affect our sleep hygiene. Caffeine is found in coffee and tea as well as chocolate, energy and fizzy drinks18,19.

Foods which are hard to digest. Our bodies continue to process foods once we are asleep, and this can keep us too alert to sleep. Therefore, avoiding foods such processed meats, fried foods and dairy foods in the hours before going to sleep may be advised3,20.  

Alcohol. While commonly believed a small “nightcap” helps us sleep, drinking alcohol before going to sleep negatively affects our sleep quality, causing us to wake repeatedly throughout the night18,19.

Advice to reduce our tiredness and improve our sleep hygiene.

Things we can do throughout the day include3,18,19:

1. Eating 5-a-day. This may be in the form of fresh, frozen or tinned fruit and vegetables or a 75g portion of legumes.

Eating some protein. For example, from lean meats, fish, dairy and soy products.

Swapping unsaturated fats in and unsaturated fats out. For example, having extra virgin olive oil instead of butter.

Participating in regular exercise. This is throughout the day and may include incidental exercise such as walking to work instead of driving.

Things we can be considerate of in the two to six hours before going to bed include3, 8, 18,19,21:

1. Avoiding caffeinated drinks. Check the labels if you are unsure if it contains caffeine; for example, green tea contains caffeine. Swap for caffeine-free alternatives such as herbal teas, fresh mint water or warm milk.

Trying to avoid large meals. Instead, if feeling hungry, have a light snack. Consider what food you are eating before bed; it is advised to avoid heavy, spicy and sugary foods.

Avoiding drinking alcohol. Instead, try enjoying one of the drinks suggested in the first point.

Other things to consider close include not exercising in the two hours before bed, reducing screen time before bed and taking part in a relaxation routine before bed, such as breathing exercises or meditation.   

It is important to remember to do what works for you, what you enjoy and what fits into your lifestyle. If you enjoy a cup of tea before bed, that is OK. If you find cutting caffeine out is something which works for you that is OK too. Moreover, cutting something out does not mean you can never have it again.

Resources to help us.

• The Sleep Foundation. A charity supporting people with sleep disorders22.

• Mind. A charity offering support for people with mental health disorders23.

• The Little Book of Calm Penguin by Paul Wilson. A book with sleep advice24.

• Pzizz. A free app designed to support sleep25.


This blog post was written by Emilia Fish, a Food Science and Nutrition graduate and MSc Clinical and Public Health Nutrition student at UCL. She has recently interned as part of the Nutrition Rocks team and enjoys sharing simple, evidence-based nutrition on @nutritionnourishment. Emilia has recently launched a podcast: The Nutrition Nourishment Podcast: Sharing Our Journeys.



























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