Researchers at the University of Chicago Medicine and Columbia University report that eating more fruits and vegetables during the day was associated with better sleep that night in healthy young adults. Meeting a five‑cup daily intake used to represent CDC recommendations was linked to an estimated 16% improvement in sleep quality, based on objective measures. The authors describe this as the first study to show a same‑day association between diet and objectively measured sleep.
Scientists have long documented that poor sleep can nudge people toward higher‑fat, higher‑sugar diets. Far fewer studies have examined the reverse. New research published in June 2025 in Sleep Health reports a same‑day link between what people eat and how well they sleep that night, measured with wrist actigraphy.
In the study, 34 healthy younger adults logged daily food intake using a standardized app while wearing wrist monitors to track sleep. The team analyzed sleep fragmentation—how often sleep is disrupted by awakenings or shifts to lighter stages. Greater daytime consumption of fruits and vegetables, as well as complex carbohydrates such as whole grains, was associated with less fragmented, more uninterrupted sleep that night.
Using statistical modeling, the researchers estimated that reaching a five‑cup daily target for fruits and vegetables—used in the study to represent CDC dietary recommendations—corresponded to about a 16% improvement in sleep quality versus no intake. “16 percent is a highly significant difference,” said co‑senior author Esra Tasali, MD, director of the UChicago Sleep Center. “It’s remarkable that such a meaningful change could be observed within less than 24 hours.”
“Dietary modifications could be a new, natural and cost‑effective approach to achieve better sleep,” Tasali added. Co‑senior author Marie‑Pierre St‑Onge, PhD, director of Columbia’s Center of Excellence for Sleep & Circadian Research, said, “Small changes can impact sleep. That is empowering—better rest is within your control.”
The authors emphasize the findings are observational and do not prove causation. They plan additional research to test causality, probe biological mechanisms, and evaluate broader populations. The work adds to evidence that aligning daily eating patterns with healthy dietary guidance may support better sleep—an outcome tied in prior research to cardiovascular and metabolic health, memory, mood, and productivity.