Poor sleep is usually blamed on stress, work, screens, anxiety, or a burnout. Far fewer people stop to consider what happened at the dinner table hours earlier.
That late-night takeaway meal. The wine used to “wind down”. The bubble tea after work. The heavy supper after skipping meals all day. These routines have become so familiar that they no longer feel connected to poor sleep at all. Instead, waking exhausted, restless, or unrefreshed has gradually become something many adults simply learn to live with.
Falling asleep quickly doesn’t always mean sleep quality is good. Repeated waking at 3am, feeling bloated during the night, or sleeping through the night yet still feeling exhausted the next morning are patterns that often go unexplained.
Sleep trackers, supplements, melatonin products, wearable devices, and online sleep advice have become increasingly common. Food and eating patterns, however, are still rarely discussed when people try to understand why they’re sleeping poorly.
Why food and sleep may be more connected than realised
Modern routines rarely leave much space for consistent eating patterns. Long workdays, irregular schedules, late commutes, shift work, social dinners, and around-the-clock stimulation have blurred the boundaries between work, eating, rest, and recovery.
Caffeine often becomes part of staying functional during the day, while alcohol, desserts, takeaway meals, or late-night snacks become associated with switching off afterwards. What begins as convenience or coping can gradually turn into a cycle of exhaustion, poor sleep, and reliance on the very habits that may be worsening both.
While stress and screen time are often blamed for insomnia, diet may be a more overlooked contributor to poor sleep than many people realise. According to Prof St-Onge, Professor of Nutritional Medicine, people tend to identify obvious sleep disruptors more easily, such as late heavy meals, caffeine, or alcohol consumption.
However, the role of an overall dietary pattern is often less obvious because people tend to focus more on what disrupts sleep than what consistently supports it. When sleep is poor, obvious culprits are easier to identify. But when sleep is good, many people don’t stop to consider the everyday habits that may have contributed to it.
In Prof St-Onge’s view, a healthful diet forms part of the foundation for overall health, including healthy sleep. While individual foods are unlikely to immediately “fix” insomnia, long-term dietary habits can influence how the body regulates energy, digestion, inflammation, and overall sleep quality over time.
This is also where modern dietary patterns may become relevant. Prof St-Onge notes that research has shown diets higher in glycaemic index and glycaemic load, particularly those with higher intakes of added sugars and refined carbohydrates, are associated with a greater risk of insomnia later on. Higher consumption of ultra-processed foods has also been linked to an increased risk of insomnia.
These dietary patterns may not only affect blood sugar regulation and energy balance, but may also gradually displace more nutrient-dense foods within the overall diet. Over time, this can reduce intake of nutrients involved in healthy sleep regulation, while contributing to broader metabolic and inflammatory disruptions that may affect sleep quality.
How modern evening habits may be affecting sleep quality
Eating patterns have increasingly shifted later into the evening, particularly among people juggling long workdays, irregular schedules, and late nights. Late-night eating isn’t automatically unhealthy. But heavy dinners, alcohol close to bedtime, oversized portions, sugary desserts, and caffeine late in the day may affect sleep more than people realise.
The distinction between “fuel”, “comfort”, and “coping mechanism” has also become increasingly blurred. Matcha drinks, energy beverages, pre-workout supplements, and high-caffeine wellness products are now woven into the routines of many people trying to push through exhaustion during the day while struggling to properly switch off at night.
Meal timing and late-night eating habits can affect sleep more than many people realise, although individual responses often vary. This is where personalised nutrition becomes particularly relevant, as people differ in their tolerance to caffeine, alcohol, heavy meals, and the timing of food intake.
However, some patterns are consistently recognised. Alcohol is known to contribute to overall sleep disturbances, even if it initially makes someone feel sleepy. Alcohol acts as a sedative, so it’s common for people to assume it’s helping with sleep onset. However, once the alcohol is metabolised, sleep later in the night often becomes more fragmented and less restorative. As a result, a person may fall asleep more easily initially, but obtain less restorative sleep overall.
Heavy meals close to bedtime may also interfere with sleep quality, particularly by increasing discomfort, bloating, or the risk of gastric reflux when lying down.
In general, it’s recommended that people stop eating a few hours before bedtime to allow for proper digestion and food transit before sleep. This may help reduce digestive discomfort and support better overall sleep quality.
The growing fascination with “sleep foods”
The search for quick nutritional fixes for poor sleep has intensified online in recent years. Sleep supplements, melatonin products, magnesium powders, tart cherry juice, serotonin-boosting foods, and endless nighttime wellness recommendations now dominate social media feeds.
As interest in “sleep foods” continues to grow, it has also become harder to separate evidence-based guidance from wellness marketing and social media trends.
But the focus on single ingredients may sometimes overshadow the bigger picture: irregular eating patterns, chronic sleep deprivation, heavy reliance on stimulants, and routines that leave little room for proper recovery.
Certain nutrients do play a role in sleep regulation, particularly those involved in the production of serotonin and melatonin, which help regulate sleep and circadian rhythms. According to Prof St-Onge, tryptophan is one of the key amino acids involved because it serves as a precursor for serotonin, which can then be converted into melatonin. This process also relies on nutrients such as magnesium, zinc, and certain B vitamins, which help support these metabolic pathways.
Protein-rich foods such as fish, poultry, and meat are good sources of tryptophan, while plant-based sources include nuts, seeds, legumes, and soy products. Magnesium is commonly found in leafy vegetables, legumes, nuts, and seeds, while zinc is present in seafood, nuts, seeds, and animal proteins.
Emerging research is also strengthening interest in the relationship between diet and sleep. Recent studies have explored how specific nutritional interventions, dietary patterns, and metabolic health may influence sleep outcomes, including a study published in the European Journal of Nutrition, examining a supplement combining mulberry leaf extract and tryptophan in adults with sleep complaints, as well as research published in Sleep Medicine, exploring links between dietary patterns and sleep-related measures over time.
However, the broader dietary pattern may matter more than any single “sleep food”. Rather than relying on one specific ingredient or supplement, the focus is often better placed on maintaining balanced and sustainable eating habits overall.
Research has also suggested that diet may influence sleep architecture, which refers to the different stages of sleep, including light sleep, deep sleep, and rapid-eye movement (REM) sleep. Higher intake of fibre and lower intake of saturated fats have been associated with more deep sleep, while higher intake of refined carbohydrates has been linked to more disrupted sleep. This may help explain why some people technically sleep for enough hours but still wake up feeling mentally exhausted or unrefreshed.
The overlooked relationship between blood sugar, digestion, and sleep
Researchers have also become increasingly interested in the relationship between blood sugar regulation, digestion, gut health, and sleep quality.
Waking during the night feeling shaky, overheated, hungry, bloated, or restless isn’t always immediately associated with eating patterns earlier in the day. Poor sleep can also intensify cravings for sugar, caffeine, and highly processed foods the next day, making the cycle harder to break.
Over time, disrupted sleep and irregular eating patterns can start reinforcing one another in ways that aren’t always immediately obvious, particularly when exhaustion itself has already become part of everyday life.
Overnight blood sugar fluctuations may play a larger role in sleep quality than many people realise, particularly when it comes to night awakenings and fragmented sleep. Prof St-Onge highlights that a recent study published in Sleep Health found that better glycaemic control appeared to mediate improvements in sleep quality following the use of a dietary supplement.
This highlights the close relationship between blood sugar regulation and sleep health. Daytime eating patterns, including the overall quality, balance, and timing of meals, may influence how stable blood glucose levels remain throughout the night. When blood sugar regulation is disrupted, some people may experience poorer sleep continuity or more frequent awakenings, although this relationship can vary between individuals.
One reason this may happen is that the body naturally aims to maintain stable blood glucose levels. When blood sugar spikes, the body activates a counter-regulatory response to bring levels back toward normal. Prof St-Onge explains that this process may trigger brief arousals and shift sleep into lighter stages, even if the person doesn’t fully wake up. Over time, this may reduce the amount of deep, restorative sleep, leaving someone feeling mentally exhausted or unrefreshed the next morning despite technically sleeping through the night.
Rather than focusing only on individual foods, the findings further support the importance of maintaining consistent and balanced dietary patterns that help support metabolic health overall.
When poor sleep may require more than dietary changes
Dietary changes are now among the most common things people experiment with when sleep problems persist. Supplements, restrictive diets, online wellness advice, and “sleep optimisation” products have become increasingly common, particularly among those trying to manage persistent exhaustion on their own.
But persistent sleep disruption isn’t always simply a nutrition issue. Repeated waking, reflux symptoms, heavy snoring, waking unrefreshed despite enough hours in bed, or ongoing daytime fatigue may sometimes point to sleep disorders, stress-related issues, breathing problems, hormonal changes, mental health conditions, or other underlying health concerns that require broader medical or behavioural support.
Dietary changes are often one of the first adjustments people make when trying to improve poor sleep. While improving diet may support overall sleep health, experts caution that dietary supplements should ideally be taken in consultation with a healthcare professional, particularly when insomnia symptoms persist.
Insomnia itself can also present in different ways. Some people experience transient or short-term insomnia, which may occur during periods of stress, travel, illness, or temporary lifestyle disruption and eventually improve. However, when symptoms such as difficulty falling asleep, staying asleep, or waking too early occur more than three times per week for at least three months, and begin causing distress or affecting daytime functioning, it may meet the criteria for chronic insomnia.
At that stage, medical attention should be sought rather than relying solely on self-directed dietary changes or supplements. Persistent insomnia may require further assessment, behavioural interventions, or evaluation for other contributing medical or psychological factors.
Poor sleep is also not always recognised immediately because many people gradually adapt to functioning while tired. Changes in mood, appetite, daytime alertness, and the ability to maintain wakefulness or vigilance can all be outward signs that sleep quality may not be optimal. Waking up feeling persistently unrefreshed, despite technically getting enough hours of sleep, may also suggest that sleep quality is sub-optimal and warrants discussion with a healthcare professional if symptoms continue.
The bigger surprise may not be that food can affect sleep. It may be how easily exhaustion, late nights, stimulants, and poor sleep had stopped feeling unhealthy at all.
Prof Marie-Pierre St-Onge, PhD
Professor of Nutritional Medicine and Director of the Center of Excellence for Sleep & Circadian Research
Columbia University, USA
LinkedIn @Marie-Pierre St-Onge
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