Can your diet affect your sleep?

Whilst we may not think about diet and sleep being connected, what we eat can influence our sleep. 

Since quality sleep is so valuable, it’s worthwhile thinking about the relationship between what we eat and how we sleep.

You have probably heard people talk about having a glass of warm milk before bed and for some, it may help them sleep, however, let's dive in and see how diet may affect our sleep and if different foods have different impacts. 

What foods should I eat for better sleep?

Research has shown a Mediterranean style diet which is rich in fruits, vegetables, nuts, seeds, extra virgin olive oil, oily fish and legumes, has been linked with better sleep The lower intake of sugar alcohol and saturated fats in the Mediterranean pattern of eating could also be an additional benefit. 

Many of these foods such as fruit, vegetables, nuts, seeds and legumes are high in dietary fibre which research shows, relates to better overall sleep quality, higher sleep efficiency and fewer sleep disturbances. 

What food could you include in your day?

Eating a Mediterranean style of diet or as per the Australian Guide to Healthy Eating would include many of these high fibre nutritious foods. 

•  2 fruit and 5 vegetables a day and a handful of nuts is a good place to start. 

Certain foods such as kiwifruit and drinking tart cherry juice may help with sleep improvements in people with sleep disorders, but these are no miracle cure:

• One study with kiwifruits had participants eat 2 kiwifruits 1 hour before bed with some improvements in sleep. 
• Another study with participants drinking tart cherry juice concentrate before bed may have a benefit for those suffering with sleep disturbances. 

Both kiwifruit and tart cherry’s contain a hormone called melatonin which is involved in regulating sleep. This might explain research which suggests there might be some improvements in sleep, however more research is needed.

Kiwifruit is a nutritious food to eat, with plenty of dietary fibre, vitamins and minerals, so eating these regularly in your diet is good for general health.  . 

What foods should I avoid for a good night's sleep?

Alcohol

Although alcohol might help you fall asleep it interferes with your sleep quality, so it might be worth considering your intake. Alcohol also has a diuretic effect, meaning it increases the passing of urine which may wake you during the night, disturbing your sleep further.

Caffeine

Caffeinated foods such as green and black tea, coffee and caffeine containing soft and energy drinks might keep you awake as they give you a sense of alertness.

Research has also shown that ingesting caffeine even 6 hours before bed can delay the onset of sleep for some people. However, some people can have caffeine close to bed and not be impacted. This is due to genetic differences and a gene that controls the rate of caffeine breakdown in the body where some people metabolise, or breakdown caffeine faster than others. 

High fat foods

Eating high fat foods, particularly saturated fat, closer to bedtime may contribute to poor sleep. High fat foods such as fried food, biscuits, cakes and fatty meats take longer to digest and if eaten later in the evening when the digestive system is starting to shut down, may be an explanation as to why they may interfere with the ability to fall asleep. They may also exacerbate reflux and interfere with your sleep. 

What about lack of sleep and the impact on appetite control and body weight?

There are a few ways in which sleep may influence our body weight. Healthy sleep duration and quality of sleep can improve food choices, where lack of sleep can increase hunger and food cravings. 

Appetite:

It is thought that sleep may affect our appetite. Our appetite is influenced by two hormones gherlin and leptin. Gherlin promotes hunger whilst leptin promotes feeling full and levels of these fluctuate over the day. It is thought that lack of sleep may affect the regulation of these hormones by reducing activity in part of the brain that controls appetite with increases in gherlin and decreases in leptin, therefore making you feel more hungry. 

Food desires:

Lack of sleep may also influence what we choose to eat, increasing our desire for high energy (calorie) foods by increased activity in part of the brain that influence, ‘food desirability and pleasure’. We may find ourselves craving sweet, sugary foods to try and boost our energy levels when feeling tired. 

Metabolism:

Aligning our body clock with the body's metabolic activities influences things such as blood sugar control which is important for reducing our risk of long term health conditions such as diabetes. It can play a part in body weight management. 

Research around this biological clock and timing of eating is known as chrononutrition. It is suggesting we keep our eating within a 10 hour or less window and at times our body is expecting to eat such as during the day time rather than night and keeping our evening meal earlier.

It seems a good night's sleep and eating during the day rather than night may be beneficial for weight management, although further research is still needed. 

For a good night’s sleep it seems to come back to the general guidelines for good health, a diet rich in plant foods such as fruit, vegetables, nuts, seeds and legumes along with some lean meat, fish and dairy. 

Good sleep will then support you choosing nourishing foods and continuing the cycle, with a good diet promoting good sleep and good sleep promoting a good diet. They work hand in hand!

Reviewed by the healthylife Advisory Board August 2023