Studies have found that what we eat significantly impacts the length and quality of our sleep. Diets high in sugar and processed foods can lead to poorer quality sleep, while caffeine and large meals before bed cause further disruptions.
Healthy, balanced diets with plenty of vegetables, oily fish, and vitamin D, like the Mediterranean diet, can lead to better sleep. But it’s not just about what we eat – it’s what we don’t eat enough of – that can affect our sleep, too.
How your diet affects your sleep quality
Not having enough healthy fats, carbohydrates, or protein has all been linked to less or worse quality sleep. Here's how these nutrients can impact sleep:
- A lack of protein can leave you feeling fatigued and weak.
- Not getting enough complex carbs and fibre has been linked to shorter sleep.
- Processed carbs, which cause blood sugar spikes and crashes, can lead to disrupted sleep.
- Diets with low levels of healthy fats have been linked with poorer quality sleep.
How poor sleep affects your diet and health
Our health, age, and personal circumstances can all affect how much sleep we need. However, poor quality sleep can have significant impacts at any age.
How much sleep do I need?
According to the NHS, adults (18-64) should get about seven to nine hours of sleep each night, while children and teens need between nine and 13 hours.
Not getting enough sleep can disrupt your metabolic process. This can increase your risk of obesity, diabetes, high blood pressure, stroke, and heart disease. It can also weaken your immune system and raise your chances of depression and stress. It can cause fatigue and low mood. This makes it harder to concentrate and affects your memory.
When we don’t get enough sleep, we can feel hungrier, more stressed and irritable. Not getting enough sleep leads to hormonal changes in your body (lower leptin and higher ghrelin), which can make you crave high-fat, high-sugar foods and increase your appetite. Continued fatigue from poor sleep can make you less likely to exercise and more likely to make unhealthy food choices.
Practical nutrition tips for better sleep
How can you eat better to sleep better? Try to:
- Eat a balanced diet. Focus on having a balanced diet with enough macronutrients (protein, fat, and carbohydrates).
- Focus on fruit and veg. High in fibre and vitamins, some fruits and vegetables have been linked to better sleep. Getting enough fibre can help you to sleep more deeply. Fibre helps stabilise blood sugar and supports a healthy gut microbiome. Your microbiome helps regulate relaxation and sleep through your gut-brain axis. Fibre also helps promote slow-wave sleep as carbs are digested and absorbed.
- Consider your timings. Avoid large, sugary meals, alcohol, and caffeine close to bedtime. Have a light, balanced meal three hours before bed. This helps keep your circadian rhythm on track.
- Get your vitamin D levels checked. Lack of vitamin D might hurt your sleep, studies say. A 2018 systematic review and meta-analysis into the association between vitamin D deficiency and sleep disorders found that a vitamin D deficiency is associated with a higher risk of sleep disorders. In the UK, getting enough vitamin D through a combination of sun exposure and diet can be tough. There are things you can do to enhance your vitamin D absorption.
- Minimise sleep disruptors. Avoid tea, coffee, fizzy drinks, and energy drinks with caffeine. They can disrupt your sleep for up to six hours before bedtime.
- Listen to your body. If you have acid reflux, avoid foods that upset your stomach before bed. Avoiding spicy, fried, or high-fat foods can reduce your likelihood of acid reflux.
Foods to eat to sleep better
There are many different healthy foods you can eat to help promote a better night’s sleep. Try and eat more:
- Melatonin-rich foods like nuts, milk and dairy, kiwi, and tart cherries.
- Tryptophan-rich foods such as fatty fish (tuna, salmon), seeds and nuts, eggs and dairy, as well as poultry.
- Magnesium and potassium-rich foods, including leafy greens, sweet potatoes, avocados, and bananas.
Remember: When you eat can be just as impactful as what you eat. A study published in 2020, into When to eat: The importance of eating patterns in health and disease revealed that three key habits we should keep in mind include:
- Eating all meals and snacks within 12 hours each day (e.g, if you eat breakfast at 7am, you should have dinner by 7pm).
- Eat most calories earlier in the day. Have bigger meals in the morning and midday, and lighter meals in the evening.
- Avoid eating close to bedtime, when sleeping, or very early in the morning.
These habits work to the favour of your digestive system, circadian rhythms and hormone production. These three factors play a huge role in both your ability to sleep, and your sleep quality.
Digestive system: Eating close to your sleep window keeps your digestive system active when you’re trying to sleep. This can cause indigestion, bloating and discomfort due to metabolic systems slowing up to 50% when sleeping, hindering restorative sleep. Experts suggest your last meal should be 2-3 hours before bed, for optimal digestion.
Circadian rhythms: Irregularity in meal times and eating late at night can disrupt your body's internal clock. Naturally, this can make falling asleep harder, set the conditions for a poorer night’s sleep and disrupt the cycle of your wake and rest windows. The science of matching your body clock to the timing of your meals is known as chrononutrition, and habit #1 (eating all meals within 12 hours of the day) is a great way to start.
Hormone production: While dependant on the food content, eating late at night can cause blood sugar spikes, which promotes the release of both cortisol and adrenaline – both of which are hormones that are counterproductive to sleep.
FAQs
What nutrient helps you sleep better?
Key nutrients can help you sleep better. Magnesium can help muscles relax and lower stress hormone levels. Tryptophan (which converts into serotonin and melatonin) helps regulate sleep. Melatonin, made by your body and found in some foods, helps control your sleep-wake cycle. Vitamin D helps align your sleep-wake cycle, while B vitamins can help with healthy sleep patterns.
What nutrient deficiency causes poor sleep?
Vitamin deficiencies can contribute to poor sleep. Low levels of vitamin C are associated with shorter, less restful sleep. B6, B9, and B19, vitamin D, iron, and magnesium deficiencies can disrupt sleep-regulating hormones. This can cause physical symptoms that disrupt sleep, like muscle cramps, or upset your body’s internal clock.
Do you digest food while sleeping?
While we continue to digest food while sleeping, it’s different from digestion during the day. While we sleep, the muscles that move food through our bodies slow down. This is why acid reflux often happens at night. It also explains why most of us don’t wake up needing a bowel movement at night.
Can low-carb diets cause sleep problems?
Eating less or having a low-carb diet can affect your sleep. Low-carb diets may lower tryptophan, an amino acid that makes serotonin and melatonin. In contrast, high-protein diets can boost epinephrine and norepinephrine, which help keep you awake. Calorie restriction can also negatively affect sleep quality. Choosing complex carbs earlier in the day and sleep-promoting foods may help.
When to work with a nutritional professional
If you’re finding it hard to get a restful night’s sleep and think your diet may be part of the problem, it could be time to seek professional support.
A qualified nutrition professional can help you:
- Identify underlying nutritional or lifestyle factors that may be affecting your sleep.
- Create a personalised eating plan to support better rest.
- Develop long-term, sustainable habits for improved well-being.
This kind of tailored guidance can make a real difference to your sleep quality and overall health.
When to speak to your GP about sleep problems
If you’ve been struggling with sleep for several months, haven’t seen improvement from lifestyle changes, or find that poor sleep is affecting your daily life, it’s important to speak to your GP.
You should also seek medical advice if:
- You or your partner notices your breathing stops and starts during sleep
- You make gasping or choking sounds while asleep
- You feel very tired during the day, even after a full night’s sleep
These symptoms may be signs of sleep apnoea or another underlying health condition. Your GP can assess possible causes and recommend the right treatment or support.
Find a nutritional professional
If restless nights or groggy mornings are becoming common, the right nutrition could help you feel more rested and energised. With expert support and mindful food choices, you can nurture better sleep and overall well-being.