Consuming more fiber and a wider variety of plant-based foods may improve sleep quality, according to the most comprehensive study to date on the relationship between diet and sleep. Researchers from the Weizmann Institute of Science in Israel analyzed data from over 3,500 adults and found significant correlations between dietary habits and sleep stages measured with FDA-approved sensors.
The Connection Between Fiber and Sleep
The study revealed that participants who ate more than the average 21 grams of fiber per day (roughly 2.5 cups of peas) spent 3.4% more time in deep, restorative sleep (N3) and 2.3% less time in lighter sleep phases. This shift towards deeper sleep is considered beneficial for brain and body health.
Why does fiber matter? Current research suggests that gut bacteria ferment fiber into short-chain fatty acids, like butyrate, which reduce inflammation and influence the gut-brain axis. This interaction may promote deeper sleep by signaling the nervous system to calm down. Additionally, higher fiber intake was linked to a slightly lower heart rate during sleep – an indicator of deeper rest and reduced cardiovascular strain over the long term.
Plant Variety and Sleep Onset
Beyond fiber, the study also found that those who consumed more than five types of plant-based foods daily fell asleep faster and had lower heart rates during sleep. This suggests that a broader range of nutrients, including vitamins, minerals, and polyphenols, may help reduce inflammation and shift the nervous system into a “rest and digest” mode.
Limitations and Future Research
While the study controlled for factors like age, sex, caffeine, and prior-day diet, more research is needed. Ideally, future trials should randomly assign participants to different diets to confirm these findings in controlled settings like sleep clinics.
The bottom line: Increasing fiber intake and diversifying plant-based foods in your diet could be a simple, low-risk strategy for improving sleep quality and overall health.
