Night Owls Who Want Better Sleep Shouldn't Overlook This Habit
Warm milk, tart cherries, kiwi: the foods that get recommended for sleep usually earn that reputation from melatonin, the hormone your body releases as light fades.
Eating a bit more of it sounds like a reasonable place to start. But how late at night that food gets eaten draws far less attention than what's in it.
New research1 from Istanbul measured both in the same group of adults, along with each person's natural leaning toward mornings or nights, then compared all three against sleep quality.
About the study
Evening body clocks are already tied to more sleep trouble and more irregular eating, but they're rarely studied alongside melatonin from food. So the researchers set out to see which of the three tracked most closely with poor sleep.
They surveyed 325 adults ages 18 to 65 in Istanbul, Türkiye, using standard questionnaires for sleep quality, chronotype (whether your natural rhythm leans toward early mornings or later nights), and night eating, which was scored with questions about morning appetite, eating after dinner, waking up to eat, food cravings, and mood.
A food questionnaire estimated how much melatonin participants were getting from their diets.
People taking melatonin supplements, antidepressants, or sleep medications were excluded, keeping the focus on food and everyday habits rather than medication use.
Late-night eating tracked most closely with poor sleep
More than half of the participants fell into the poor-sleep range.
Of the factors the researchers looked at, night eating had the strongest link with sleep quality: People who scored higher on the night-eating questionnaire also tended to report worse sleep.
A preference for evenings was linked to poorer sleep, too, but the connection was weaker. Being a woman and having a chronic health condition were also associated with poorer sleep in this group.
Dietary melatonin told a different story.
After the researchers accounted for the other factors, neither the total amount of melatonin people got from food nor the amount they consumed in the evening was associated with sleep quality.
What the melatonin result does & doesn't mean
The three measures formed a pattern: A stronger preference for evenings was linked to more night eating, which was linked to poorer sleep.
But because everyone was surveyed once, the researchers couldn't say that one caused the next.
The melatonin finding also needs context. Dietary intake was relatively low, and food's melatonin content can vary with factors like ripeness, storage, and cooking.
The researchers estimated intake from published food values rather than measuring melatonin directly. Plus, foods like sour cherries and milk contain other compounds that could influence sleep.
The study also relied on self-reported habits, included mostly women from one city, and didn't account for factors like caffeine, stress, exercise, or evening light.
So it's an interesting link, but not a reason to overhaul your nighttime routine.
How to work with your own rhythm tonight
Nothing here was tested as an intervention, so treat these as low-risk experiments rather than rules. If you're already thinking about eating habits for sleep, timing is worth watching alongside what lands on the plate.
- Notice your night eating: If you tend to snack late at night, jot down which nights that happens and how you feel the next morning. A week of casual notes can surface a pattern before you change anything.
- Keep your timing steady: If you're a night owl by nature, consistent sleep and meal times that suit your own rhythm are usually easier to stick with than a schedule you're fighting.
The takeaway
Sleep advice tends to focus on what you add to your evening, whether that's a supplement, a food, or a bedtime tea.
This research points to the clock instead, with late eating showing a closer tie to sleep quality than the melatonin in what's eaten. A week of notes on when you eat after dinner will tell you more about your own nights than any average can.
