Most people try to follow a nutritious diet so they feel alert and healthy during the day. But a new study shows that eating more fruits and vegetables can lead to benefits while you’re asleep, too.
The study, published June 11 in Sleep Health, found that participants saw a 16% improvement in sleep quality when they increased their fruit and vegetable intake from zero to five cups per day.
In fact, the improvements were fairly immediate—greater fruit and vegetable consumption led to less fragmented sleep the subsequent night, the study found.
The results indicate that simple dietary changes could help you rest easy at night, and empower people to focus on the do’s of better sleep, rather than the don’ts, study author Marie-Pierre St-Onge, PhD, professor of nutritional medicine and director of the Center of Excellence for Sleep and Circadian Research at the Columbia University Irving Medical Center, told Health.
“We often make recommendations for things to avoid for healthful sleep—don’t drink caffeine too late, don’t drink too much alcohol,” St-Onge told Health. “It’s good to know that there are foods that will lead to better sleep.”
To investigate how daily eating patterns might affect sleep, St-Onge and the other researchers recruited 34 participants between the ages of 20 and 49, the majority of whom were men. To start, all of the participants were in good health and didn’t have any history of sleep problems.
The study included two six-week phases, with a month between each. The research team asked participants to record all foods and beverages they consumed over multiple 24-hour periods, and also tracked their sleep with wrist actigraphy (a smartwatch-esque monitor).
At the end of the study, the researchers looked for links between participants’ diets and their sleep quality. Specifically, they looked at fragmented sleep, or the amount of times participants woke up throughout the night, St-Onge explained.
The data showed that:
- Greater daytime intake of fruits and vegetables was associated with less disrupted sleep
- Greater carbohydrate and fiber intake was linked to better sleep quality
- Greater red and processed meat consumption was associated with worse sleep
In particular, increasing from zero to five daily cups of fruits and vegetables was linked to a 16% improved sleep quality.
Interestingly, added sugar was not linked to sleep quality, indicating that “carbohydrates and fiber from fruits and vegetables are most likely contributing to better sleep quality,” the study authors wrote.
Essentially, this means that a person’s daily eating habits can directly influence how well they sleep at night, explained Brannon Blount, MS, RDN, a registered dietitian based in Virginia.
“While we often think of sleep and diet as separate wellness goals, this research connects the two in a meaningful way,” she told Health.
This is certainly not the first study to investigate the connection between diet and sleep, experts agreed.
Previous research has shown that people who follow the Mediterranean diet or other healthy eating plans also have a lower risk of insomnia and sleep disorders, St-Onge explained. And in 2016, her team found that a higher fiber intake was associated with deeper sleep, while more carbohydrates and added sugars were related to increasingly disrupted sleep.
Research published in 2021 also found that women who added more servings of fruits and vegetables to their diets experienced improved insomnia symptoms and better sleep quality, and took less time to fall asleep.
This study indicates that what you eat during the day can have a direct effect on your sleep the following night—that’s the most important finding, Erica Jansen, PhD, MPH, assistant professor of nutritional sciences at the University of Michigan School of Public Health, told Health.
That specificity is “different from most observational studies, which often look at how people usually eat with how they usually sleep,” said Jansen.
There are, of course, possible caveats. People tend to eat more food when they’re tired, for one, so sleep could be influencing diet, not the other way around. “You tend to choose higher-fat foods and higher-sugar foods because the lack of sleep distorts your taste perceptions,” St-Onge explained.
It’s also true that people who eat nutritiously are more likely to lead healthier lifestyles in general—they may exercise more frequently, which leads to better sleep. However, this was taken into consideration for this study, said St-Onge.
“We can adjust for all of these factors, and even when we do, we’re finding that it is in fact the healthful diet that is associated with better sleep,” she said.
Still, St-Onge acknowledged there’s still many questions to be answered, including what the actual mechanism might be behind food’s impact on sleep.
For now, the most supported theory is that carbohydrates can increase the brain’s uptake of dietary tryptophan. “This is an amino acid that gets converted to serotonin and then melatonin, the hormone that regulates sleep,” explained Blount.
Fruits and vegetables are also rich in fiber, vitamins, and antioxidants, which promote better brain, hormone, and gut health, Jansen and Blount added. That could, in turn, support better sleep.
The task of getting enough fruits and veggies in your diet every day can feel overwhelming, St-Onge said. But small changes make the task simpler.
It can actually be fairly easy to add one or two cups of vegetables to your meals: Try having a side salad with your meal, or throw some spinach in your soup or pasta, she recommended.
St-Onge said she always has a plate of raw vegetables on the table for snacking, too.
It’s also important to focus on adding more vegetables and fruits to your diet, rather than excluding other less nutritious foods, added Sheri Gaw, RDN, a registered dietitian at the El Camino Hospital Cardiac and Pulmonary Wellness Center.
“Try to include a fruit or veggie with every meal or snack,” Gaw told Health. “You may find you have less of a desire for foods with less nourishment.”
Another way to make it easy on yourself? Fruits and vegetables are still healthy even if they’re not freshly prepared. “Frozen, canned, pre-washed, and pre-cut options all count and can help you get closer to that five-cup goal without a lot of extra time or effort,” Blount explained.
At the end of the day, incorporating fruits and vegetables looks different for every person—the key is to find a method that works best for you, said Jansen.
“There doesn’t need to be a focus on any one particular sleep-promoting food,” she said. “Eating a banana at breakfast or packing a baggie of baby carrots at lunch may be an easy way to start incorporating more into your daily routine.”
