Eat better, sleep better: Study reveals “same-day” impact of diet on sleep quality

From white noise machines to melatonin supplements and weighted blankets, the market for rest and relaxation is continually growing. However, a new study suggests that one of the most effective solutions may already be in the kitchen: fruits and vegetables. Researchers from the University of Chicago Medicine (UChicago), US, and Columbia University, New York, US, reveal that eating more fruits and vegetables during the day is linked to better sleep quality that same night.

According to the researchers, the peer-reviewed study offers some of the strongest evidence yet that what we eat directly influences how well we sleep — potentially opening up new avenues for tackling widespread sleep-related health issues through diet.

“Dietary modifications could be a new, natural, and cost-effective approach to achieve better sleep,” explains co-senior author Esra Tasali, MD, director of the UChicago Sleep Center. “The temporal associations and objectively measured outcomes in this study represent crucial steps toward filling a gap in important public health knowledge.”

Diet and sleep — a two-way street

While previous research has shown that sleep deprivation often leads to poor dietary choices — such as eating more sugar and fat — far less is known about how daytime diet impacts sleep itself. This latest study breaks fresh ground by showing a same-day connection between fruit and vegetable intake and objectively measured sleep outcomes.

The research team recruited healthy young adults, who logged their food intake using a mobile app and wore wrist monitors to track their sleep. The scientists specifically measured “sleep fragmentation” — a key indicator of how often a person wakes up or transitions from deep to light sleep.

The results show that participants who ate more fruits and vegetables, along with healthy carbs like whole grains, had deeper, less interrupted sleep. Moreover, statistical modeling showed that consuming the Centers for Disease Control (CDC) recommended five cups of fruits and vegetables per day could improve sleep quality by up to 16% compared to those who ate none.

“Sixteen16 percent is a highly significant difference,” Tasali emphasizes. “It’s remarkable that such a meaningful change could be observed within less than 24 hours.”

Small change, big results

The study’s findings suggest that even short-term improvements in diet can have immediate effects on sleep, reinforcing that current dietary guidelines are applicable to metabolic and cardiovascular health and for better sleep.

While the study focused on healthy young adults, researchers say the implications may extend across age groups and health conditions. The authors also highlight that future research will investigate causality, underlying biological mechanisms, and how these findings hold up in larger, more diverse populations, which may hold potential for the supplements and functional ingredients industries.

“People are always asking me if there are things they can eat that will help them sleep better,” concludes co-senior author Marie-Pierre St-Onge, Ph.D., director of the Center of Excellence for Sleep & Circadian Research at Columbia, concludes. “Small changes can impact sleep. That is empowering — better rest is within your control.”