Could Your Diet Be Ruining Your Sleep?

Is your bedtime snack causing a blood sugar rollercoaster? 

What you eat in the hours before bed may influence how well you sleep, and large amounts of sugary foods close to bedtime may be one factor to consider. Foods high in free sugars can cause blood glucose levels to rise quickly, followed by a drop as your body brings blood sugar back towards its usual range. For some people, these fluctuations may contribute to hunger, restlessness or waking during the night. 

This doesn’t mean you need to avoid carbohydrates in the evening or never enjoy something sweet after dinner. Instead, pay attention to what you are eating right before bed, or in the couple of hours before. If you’re hungry, choosing a snack that mixes the right combination of nutrients can provide a more balanced source of energy that won’t have you waking at 1am for a snack. Think Greek yoghurt with kiwi, oatcakes with nut butter or a small bowl of porridge with cherries.

Amie explains:

“Think beyond sugar alone. Pairing a carbohydrate-rich food with protein, fibre or healthy fats can help slow digestion and provide a steadier release of energy. So, if you fancy something sweet in the evening, try pairing it with a source of protein, such as fruit with Greek yoghurt. And if your 9pm chocolate fix is non-negotiable, there’s no need to cut it out completely – just reduce the portion and enjoy it alongside something like Greek yoghurt. It’s a simple way to make your evening snack more balanced, without feeling like you have to give up the foods you enjoy.”

Can certain foods actually help you sleep?

There’s no single food that guarantees a good night’s sleep, but some foods provide nutrients involved in normal sleep and nervous-system functions. Nuts and seeds, wholegrains, beans and lentils, leafy green vegetables, dairy and eggs provide nutrients such as magnesium, B vitamins and tryptophan, which are involved in processes linked to sleep. 

Some foods, such as kiwis and tart cherries, have also been studied for their potential effects on sleep, although the evidence is still developing. Rather than relying on one “sleep-promoting” food, aim for a varied, balanced diet that provides a good range of nutrients. Eat regular, balanced meals made up of lean proteins, wholegrains and veggies and avoid processed foods and high sugar foods where possible. This overall dietary pattern over the long term will promote optimal sleep and rest much more than occasionally including “sleep inducing” foods. 

If you consistently eat a healthy diet already and would like to introduce some sleep supporting foods to your evenings here are some suggestions to try. All these options contain the right macronutrients to keep your blood sugar stable and avoid disruptive blood sugar spiking before bedtime.

• Greek yoghurt + kiwi: Protein-rich yoghurt with kiwi, which has been studied for its potential sleep benefits. 

• Oatcakes + almond butter: Wholegrain oats provide magnesium and complex carbohydrates, while almonds provide magnesium and healthy fats. 

• Banana + a small handful of walnuts: Provides magnesium, B vitamins and tryptophan, alongside healthy unsaturated fats. 

• Porridge + cherries: Oats provide fibre and magnesium, while cherries contain naturally occurring melatonin and polyphenols. 

• Warm milk + cinnamon: Milk provides protein and tryptophan, while a warm, caffeine-free drink can make a soothing addition to a bedtime routine. 

The surprising connection between your gut and your sleep

Your gut and sleep are more closely connected than you might think, thanks in part to the gut–brain axis, the two-way communication system linking your digestive system and brain through the nervous system, hormones and chemical signals. The trillions of microbes living in your gut can produce substances that influence processes involved in mood, stress and sleep, while your sleep and daily rhythms can also affect the gut microbiome. 

Research suggests that a healthy, diverse gut microbiome may be associated with better sleep, although we’re still learning exactly how this relationship works and which changes are most important. A diet rich in fibre, plant foods and a variety of whole foods helps support a diverse gut microbiome, which may in turn support the gut–brain connection and healthy sleep. 

Amie says:

“Fibre is also very supportive of healthy cholesterol levels, making it a win for both sleep and heart health. Making sure to include a variety of plants, such as those coming from fruits, vegetables, lentils, beans, nuts and seeds is a great way to support overall health, including sleep.” 

Does eating late really ruin your sleep?

Despite what you may have heard, there isn’t a universal cut-off time when you should stop eating. However, what, how much and how close to bedtime you eat may well affect how well you sleep. 

Eating a large or heavy meal shortly before bed can leave you feeling uncomfortable and may increase the likelihood of indigestion or reflux, which can make it harder to settle and stay asleep. Meal timing may also interact with our body’s natural circadian rhythms, including the release of melatonin, although the relationship between when we eat and sleep is complex and still being researched. Rather than worrying about a specific time, consider how close your evening meal is to bedtime and how you feel afterwards. 

If possible, give yourself some time to digest your main evening meal before going to bed. If you’re genuinely hungry later, there’s no need to go to bed hungry – choose a small, balanced and nourishing snack like the ones above.

Hydration without the 2am toilet trip

Hydration can also play a part in a good night’s sleep. Being dehydrated may leave you feeling uncomfortable or thirsty during the night, but drinking large amounts of fluid immediately before bed can have the opposite problem, sending you to the toilet and interrupting your sleep. 

The good news is that hydration doesn’t come from drinks alone. Fruit and vegetables contain a significant amount of water, while foods such as milk, yoghurt and soups can also contribute to your daily fluid intake. A varied diet also provides naturally occurring electrolytes and minerals, including potassium, magnesium and sodium, which help your body maintain the right fluid balance.

Rather than trying to catch up on your hydration in the evening, aim to drink regularly throughout the day and include plenty of water-rich foods in your meals. In the few hours before bed, avoid drinking large volumes all at once, particularly if you find that night-time trips to the toilet are disturbing your sleep.

That afternoon coffee could still be keeping you awake 

Here’s something you might not realise: six hours after drinking a caffeinated beverage, around half of the caffeine can still be present in your body. So that 3pm coffee might not feel like it should affect your bedtime, but caffeine can linger long after its initial pick-me-up has worn off. 

Both caffeine and nicotine are stimulants that can disrupt sleep. Avoiding these substances in the afternoon and evening, can help promote better sleep. Caffeine stays in the body long after it has been consumed and can hinder the quality of our sleep, even if we feel like we fall asleep easy. If you are consistently waking up feeling tired, despite getting 7-9 hours of sleep per night, try giving up caffeine after midday and see whether you notice a difference after a few weeks. 

Alcohol might make you sleepy, but is it helping you sleep?

Ever noticed that a glass of wine makes you feel sleepy? There’s a catch. While alcohol can make it easier to drift off, it can interfere with sleep quality later in the night. Alcohol, while not a stimulant, negatively impacts our sleep quality and decreases the amount of deep sleep we get. Despite us feeling like we fall asleep easier, the quality of that sleep isn’t up to scratch. 

Amie advices:

“If you are going to have an alcoholic drink, try have it earlier in the day rather than right before bed to minimise the impact on your much needed shuteye.” 

Takeaway message

There isn’t one food that guarantees a good night’s sleep. But your overall diet, along with factors such as caffeine, alcohol, meal timing and hydration, can all play a part. Rather than searching for a magic sleep-inducing food, focus on the bigger picture: a balanced, heart-healthy diet, regular meals and habits that support your sleep routine. And don’t ignore the importance of a good sleep wind-down routine too – download our Sleep Improvement Action Plan if you want to take positive steps to better sleep.