Sweet dreams? Not if you eat too much sugar
Let's start by mentioning the foods to avoid if you want to sleep well. It's perhaps no surprise to learn that the usual unhealthy suspects – sugary and fatty foods, including sweet snacks, ready meals and takeaways – can disrupt your slumber.
A low-fibre diet that's high in saturated fats and sugar is strongly linked with lighter, less restorative rest and more sleep disruptions, according to recent research at Columbia University.
These restless nights lead us to crave more sweet snacks the following day – and so the vicious circle continues.
Scientists have also pinpointed other key dietary differences between people who enjoy seven to eight hours of restorative sleep each night, and those who sleep too little or too much (that's nine hours or more).
Both short and overlong sleep are associated with lower food variety, say researchers at the Center for Sleep and Circadian Neurobiology at Penn University.
Those who regularly enjoy the optimum seven to eight hours' sleep tend to eat healthy, balanced diets with a wide range of nutrients.
An earlier study by the same team also found that poor quality sleep was linked to high fat intake.
Related: How to reduce the amount of sugar you eat
Are you getting enough magnesium?
Low magnesium intake can lead to constant sleep interruptions throughout the night, according to a report in the Journal of Orthomolecular Medicine). Or to put it another way: you may nod off without a problem, but you'll have trouble staying asleep.
Good sources of this essential mineral include green, leafy vegetables, wholegrain bread, brown rice, bananas and nuts.
Men should aim to consume 300mg magnesium per day, while women need around 270mg, according to NHS guidelines.
Related: Find out more about how magnesium benefits your health
Could tryptophan-rich foods help you sleep?
Tryptophan is an amino acid that's been found to encourage drowsiness. It plays a key role in the manufacture of the feelgood hormone serotonin, which is responsible for regulating mood, sleep and appetite.
One of the rarest amino acids, tryptophan is found in foods such as white meat, pumpkin seeds, sunflower seeds and peanuts.
However, upping your tryptophan intake alone isn't necessarily the answer. High-protein foods that are rich in tryptophan also contain an abundance of other amino acids, which tend to 'out-compete' it for access to the brain transmitter site.
The solution, it seems, is to combine protein and healthy carbohydrates, such as wholegrain bread, quinoa or brown rice, as these help transport tryptophan to the brain.
Related: How to cook quinoa, plus, delicious recipes with quinoa
What role does melatonin play?
Certain foods have been found to boost the body's natural levels of melatonin – the hormone that helps regulate the sleep-wake cycle.
Top of the list? Cherries. Drinking tart cherry juice twice a day for two weeks helped increase average sleep time by nearly 90 minutes among older adults with insomnia, researchers from Louisiana State University have found.
Another recent study, from Northumbria University, found that drinking cherry juice can improve both the quality and duration of sleep, thanks to the boost in melatonin levels. Other melatonin-boosting foods include bananas, grapes, oats and brown rice.
Related: The top 20 healthy foods to eat
And what about drinks before bedtime?
Cherry juice isn't the only drink that can aid your slumber. That old favourite, warm milk, is rich in tryptophan and calcium, which work together to encourage melatonin production. Alternatively, a cup of chamomile tea just before bedtime can also encourage restful sleep. It's thought the effect is partly due to an amino acid called glycine, which helps relax the muscles and nerves.
Other herbal teas, including passion flower and valerian, may act as a mild sedative, too. Another tip? You could try adding a teaspoonful of honey to your tea: the glucose kick will encourage the brain to shut off production of orexin, the chemical responsible for alertness.
Finally, it's a good idea to steer clear of caffeinated drinks – including coffee, tea and most soft drinks – in the evening.
And while alcohol may help you nod off initially, it certainly won't encourage restful slumber throughout the night. In fact, sleep quality will be significantly altered and disrupted, according to a study from the University of Melbourne – something you may well have already experienced for yourself.
Related: Are you drinking more alcohol than you think?