A comprehensive study of over 3,500 adults has found that consuming more dietary fibre is associated with increased time in deep sleep. Participants who ate above-average amounts of fibre spent more time in restorative sleep stages and had lower heart rates at night. Greater variety in plant-based foods also helped some fall asleep faster.
Researchers led by Hagai Rossman at the Weizmann Institute of Science in Israel analyzed dietary and sleep data from more than 3,500 adults, with an average age of 53. Over two consecutive days, participants recorded their meals using a mobile app, either during or shortly after eating. That night, they wore an FDA-approved device with sensors on the chest, wrist, and finger to monitor snoring, blood oxygen levels, heart rates, and breathing rates.
The device helped estimate time spent in different sleep stages: light sleep (N1 and N2), deep sleep (N3), and rapid eye movement (REM) sleep. Using a computational model, the team examined how 25 dietary factors influenced sleep that night, adjusting for variables like age, sex, caffeine intake, and the previous day's data. This approach allowed a clearer view of daily eating's impact on subsequent sleep.
The average fibre intake among participants was 21 grams per day, roughly equivalent to 2.5 cups of peas. Those exceeding this amount spent 3.4 percent more time in N3 deep sleep and 2.3 percent less in light sleep compared to those below average. "They’re moving in a direction of more restorative sleep, which is important for a healthier brain and body," said Marie-Pierre St-Onge at Columbia University in New York City.
Higher fibre consumption was also linked to a slightly lower nocturnal heart rate, indicating deeper rest. "A 1 beat-per-minute difference might not be that important for one night, but if that difference is sustained over decades or a lifetime, that could make an important difference for cardiovascular health," St-Onge added.
The study suggests gut microbes ferment fibre into short-chain fatty acids like butyrate, which may reduce inflammation and promote deep sleep through gut-to-brain signaling. Additionally, eating more than five types of plant-based foods daily was associated with falling asleep slightly faster and lower heart rates during sleep, possibly due to a wider range of vitamins, minerals, and polyphenols that support rest.
"Increasing fibre and plant variety is already recommended for overall health, carries low risk for most people and may offer sleep benefits as an additional upside," Rossman noted. Future randomized trials in sleep clinics are recommended to confirm these associations. The findings were published on medRxiv with DOI: 10.64898/2026.02.17.26346471.
