How a High-Fiber Diet Can Enhance Your Deep Sleep Quality

Boosting your fiber intake can significantly enhance your sleep quality. Consuming a diverse array of fruits, vegetables, and nuts may help you fall asleep faster and experience deeper sleep. This finding emerges from the most comprehensive study to date examining how our dietary choices impact sleep quality.

“Incorporating more dietary fiber and a variety of plant-based foods is already recommended for overall health, poses minimal risks for most individuals, and may enhance sleep quality,” says Hagai Rothman at the Weizmann Institute of Science in Israel.

While previous research indicated a relationship between fiber-rich, plant-based diets and improved sleep, those studies often relied on participants recalling meals from surveys, sometimes weeks or months later. Additionally, typical sleep measurements, usually obtained through movement trackers, struggle to differentiate between deep and light sleep, both vital for assessing sleep quality.

By analyzing sleep and dietary data from over 3,500 adults, averaging 53 years old and older, Rothman and his team offer the clearest insights yet. “Past research did not take into account this breadth of dietary and sleep variables,” notes Marie-Pierre Saint-Onge at Columbia University in New York City.

Participants documented their food intake using a mobile app immediately after meals over two consecutive days. At night, they wore a device approved by the U.S. Food and Drug Administration for sleep tracking, equipped with sensors that monitored snoring, blood oxygen levels, heart rate, and breathing patterns.

These measurements allowed researchers to estimate the duration of different sleep stages: light sleep (N1 and N2), deep recovery (N3), and rapid eye movement (REM) sleep—where dreams occur.

The study employed a computational model to predict the effects of 25 dietary factors on nightly sleep quality while controlling for variables such as age, gender, caffeine consumption, and previous day’s dietary and sleep data. “By controlling for the previous day, we were able to explore how that day’s choices influenced sleep the following night,” Rothman explains.

Participants consuming more than the cohort average of 21 grams of fiber daily—a quantity comparable to about 2.5 cups of peas—often reported better sleep quality than those with below-average fiber intake. For instance, those with higher fiber intake spent 3.4% more time in deep sleep (N3) and 2.3% less time in light sleep, enhancing restorative sleep vital for a healthy brain and body, according to St. Onge.

Although the exact mechanism behind fiber’s effects remains uncertain, research indicates that gut bacteria ferment fiber into short-chain fatty acids like butyrate, which alters gut-brain signaling, reducing inflammation and promoting deeper sleep, Rothman suggests.

Additionally, individuals with higher fiber intake exhibited slightly lower heart rates at night compared to those with lower levels. A lower nighttime heart rate generally signifies deeper rest and repair, easing the heart’s workload. “Even a one beat-per-minute difference [seen between high and low fiber groups] might seem minor, but persisting over years can substantially impact cardiovascular health,” emphasizes St. Onge.

Further analysis showed that those who consumed five or more plant-based foods daily fell asleep slightly faster and had lower heart rates during sleep compared to individuals eating fewer plant-based items. A wider variety of plants offers diverse vitamins, minerals, and beneficial molecules like polyphenols that contribute to reduced inflammation and promote a restful state, Rothman adds.

To verify these findings, further clinical trials are required, ideally conducted in sleep clinics where participants are randomly assigned to varying levels of fiber intake and consumption of a wider or narrower array of plant-based foods, St-Onge suggests.