Research continues to examine how diet influences sleep quality, with evidence showing that both the type of food consumed and the timing of meals play important roles.
Studies indicate that heavy evening meals may disrupt sleep, while avoiding caffeine before bedtime can also be beneficial. Some trials suggest that tart cherry juice, kiwifruit, or warm milk may improve sleep due to compounds such as tryptophan, which is a precursor of melatonin. Melatonin regulates the sleep–wake cycle and is present in foods including eggs, fish, nuts, seeds, fruit, and vegetables.
Marie-Pierre St-Onge of Columbia University noted that dietary changes throughout the day, rather than a single evening food choice, are more effective. "You can't eat poorly all day long and think that it's enough to have a glass of tart cherry juice before bedtime," she said.
Erica Jansen of the University of Michigan found in a 2021 study that increasing daily intake of fruit and vegetables improved sleep quality in more than 1,000 participants. Women were more than twice as likely to report improvements in insomnia symptoms after eating three or more extra servings of fruit and vegetables per day. A 2024 study in Spain also linked low tryptophan intake to shorter sleep duration and a greater risk of insomnia.
Researchers point out that tryptophan must be consumed with high-fibre carbohydrates, such as wholegrains or legumes, to be absorbed effectively. Plant-rich diets also contribute through reduced inflammation, higher fibre intake supporting gut health, and nutrients such as magnesium, which can lower cortisol levels and aid relaxation. Magnesium is found in leafy greens, legumes, nuts, seeds, and wholegrains, though soil depletion and processed diets mean intake is often low.
A 2024 study led by Heather Hausenblas at Jacksonville University tested magnesium supplementation and found improved deep and REM sleep among participants. However, she cautioned that supplementation is not a cure-all, as other lifestyle factors such as exercise and sleep regularity remain important.
Meal timing also influences sleep. Jansen recommended not eating large meals before bedtime, with earlier meals supporting better circadian rhythms. She noted, "When you have a clearer separation between day and night, the brain has an easier time recognising that it's time for sleep."
Research suggests that plant-rich diets and regular eating schedules may improve sleep quality, though researchers stress that factors such as physical activity, light exposure, and mental health also play important roles. St-Onge added that poor sleep should be distinguished from clinical sleep disorders, which require medical treatment alongside dietary adjustments.
Source: BBC