“Eating time cues are another way of telling our body what time it is,” Jansen says. “The body feels functions best when we’re doing the same things at the same time every day.”
And when you do eat breakfast, bear in mind that one study found that eating a dairy-rich breakfast in bright daylight may be more beneficial to sleep than eating it in a dimly lit room. This is because, researchers say, eating in the daylight allows our bodies to produce more melatonin, the hormone that helps us sleep at night.
However, St-Onge says, scientists haven’t produced any definitive answers yet on whether melatonin we might obtain from plants influences the melatonin our bodies produce, and how this might influence our sleep.
“Also, is our metabolism impacted by what we eat? This could be relevant for sleep. We need to dig further into those mechanisms,” she says.
Jansen agrees that this is a difficult area of research, with several unanswered questions, including the amount of melatonin we need in our diets for it to have an effect on sleep.
“It’s difficult to study whether light is a bigger influence on melatonin than diet, or if they work together,” she says.
Optimising our diet for sleep
It seems that a plant-rich diet is the most beneficial for sleep, for numerous reasons – and that eating at consistent times throughout the day – for those who can – may also help.
But our diet doesn’t exist in a vacuum, and researchers stress that our sleep is also influenced by how much we move in the day, our mental health, and our exposure to light and darkness.
Also, St-Onge says, it’s important to distinguish between poor sleep, and a sleep disorder, such as insomnia or sleep apnoea.
“If you have a sleep disorder, you need to get tested and treated,” says St-Onge. “Part of the treatment plan could be improving your diet, but some people will need something in addition to that.”
* Disclaimer: All content within this article is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. The BBC is not responsible or liable for any diagnosis made by a user based on the content of this site. The BBC is not liable for the contents of any external internet sites listed, nor does it endorse any commercial product or service mentioned or advised on any of the sites. Always consult your own GP if you’re in any way concerned about your health.
—
If you liked this story, sign up for The Essential List newsletter – a handpicked selection of features, videos and can’t-miss news, delivered to your inbox twice a week.
For more science, technology, environment and health stories from the BBC, follow us on Facebook and Instagram.