By Muhammad Shabbir
Publication Date: September 30, 2026
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What to Eat for Better Sleep: Fiber and Plant Foods
Sleep isn't influenced only by what happens after you get into bed. Researchers are increasingly examining whether everyday dietary choices are also associated with changes in nighttime sleep.
A 2026 study published in Nature Health examined 4,793 person-nights of dietary and wearable sleep data to investigate whether day-to-day differences in food intake were related to sleep that same night. Researchers found associations between higher fiber intake, greater plant-food variety and several measures of sleep physiology.
The findings don't establish that a particular food can cure insomnia or guarantee better sleep. Instead, they add to research examining how diet quality, fiber-rich foods and plant-forward eating patterns may relate to sleep health.
What Did the New Study Find?
The researchers analyzed real-world dietary records alongside wearable measurements of sleep.
Higher fiber density was associated with:
About 0.59 percentage points more deep sleep
About 0.76 percentage points more REM sleep
About 1.35 percentage points less light sleep
About 1.14 fewer beats per minute in average nighttime heart rate
The study also found that greater variety of plant foods and higher intake of whole-plant foods were associated with lower nighttime heart rate.
These are associations observed in the study. They should not be interpreted as proof that increasing fiber will necessarily produce the same changes in every person.
Why Are Fiber-Rich Foods Interesting?
Fiber is naturally found in foods such as:
Oats and other whole grains
Beans and lentils
Chickpeas
Fruits
Vegetables
Nuts
Seeds
If you're looking for practical ways to include more fiber-rich foods in your meals, see our guide to 25 High-Fiber Lunch Ideas to Help Support Regularity for additional meal ideas.
Previous research has also examined the relationship between fiber-rich diets and sleep. A review of human studies found that diets containing more fiber, fruits and vegetables were generally associated with better measures of sleep, although researchers noted that more rigorous research is still needed.
One possible area of interest is the relationship between dietary patterns, gut health and other biological processes. However, the exact mechanisms connecting specific dietary components with sleep remain an active area of research.
Does Eating More Plant Foods Mean Going Vegan?
Not necessarily.
The 2026 study focused on plant diversity and whole-plant food intake, rather than requiring participants to follow a vegan diet.
Plant-forward eating can simply mean including a wider variety of fruits, vegetables, legumes, whole grains, nuts and seeds in your normal diet.
Earlier research has also found that the quality of plant-based foods matters. In one study of middle-aged and older adults, a healthful plant-based dietary pattern was associated with better sleep quality, while an unhealthy plant-based pattern was associated with poorer sleep quality.
So "plant-based" does not automatically mean "healthy." A diet dominated by highly processed foods can still contain many plant-derived ingredients.
Which Plant Foods Can Add More Fiber?
Oatmeal
Oats provide dietary fiber and can be combined with fruit, nuts or seeds.
For more information about using oats and other ingredients in a nutritious breakfast, see our article Granola vs. Muesli: Which Is Better for Heart Health?.
Beans and Lentils
Legumes are naturally rich in fiber and can be added to soups, salads, curries and other meals.
Fruits
Apples, pears, berries and other whole fruits can contribute fiber while adding variety to the diet.
Vegetables
Broccoli, carrots, cabbage, leafy greens and other vegetables can help increase both fiber intake and plant diversity.
Nuts and Seeds
Almonds, walnuts, chia seeds, flaxseeds and pumpkin seeds can add plant foods and fiber to meals.
Chia and flaxseeds are particularly interesting examples of nutrient-rich seeds. Our guide Chia vs. Flaxseeds: Which Offers More Omega-3s and Fiber? compares their nutritional characteristics.
Whole Grains
Oats, brown rice and other whole-grain foods can provide more fiber than their refined counterparts.
Why Might Plant Variety Matter?
One notable part of the new research was plant diversity.
Researchers defined plant diversity according to the number of unique plant-based food items consumed during the day. Greater plant diversity was associated with lower nighttime heart rate.
This means dietary variety can come from many different foods, including legumes, vegetables, fruits, whole grains, nuts and seeds.
For another example of a nutrient-rich plant food, see Edamame for Healthy Aging: What Research Shows.
The broader idea is not to depend on one "superfood," but to include a variety of plant foods across meals.
What About Eating a Large Meal at Night?
The study produced an interesting finding about meal timing.
A greater proportion of daily calories consumed during the six hours before bedtime was associated with approximately 7.7 additional minutes of total sleep. However, it was also associated with an increase of about 0.73 beats per minute in nighttime heart rate.
This illustrates why sleep research cannot always be reduced to a simple "more is better" message.
The finding does not mean that eating a large meal before bed is a recommended strategy for improving sleep.
What Does the Research Actually Prove?
This is an important distinction.
The 2026 research used an observational causal-inference framework, real-time dietary records and wearable sleep measurements. The researchers used statistical methods designed to account for previous dietary and sleep patterns.
However, this type of evidence does not establish that eating more fiber will directly cause better sleep for every person.
The study also found that short-term changes in macronutrient distribution and micronutrient consumption did not show robust associations after false-discovery-rate correction.
In other words, the findings are more nuanced than simply identifying a single "sleep nutrient."
What Researchers Still Don't Know
The relationship between diet and sleep is complex.
Researchers still need more evidence to determine:
Which dietary components have the strongest effects on sleep
Whether changing fiber intake directly changes sleep
How individual dietary responses differ
How long-term dietary patterns influence sleep
Which biological mechanisms explain these relationships
Whether the findings translate into meaningful improvements in sleep problems such as insomnia
Previous reviews have similarly concluded that the relationship between plant-rich diets and sleep is promising but still requires additional research.
Practical Ways to Include More Fiber-Rich Foods
You don't need to focus on one particular food.
Instead, variety can be built into ordinary meals:
Breakfast: Oatmeal with berries and seeds.
Lunch: Lentils or chickpeas with vegetables and a whole grain.
Snack: Fruit with a small serving of nuts.
Dinner: Vegetables with beans, fish, poultry or another protein source alongside a whole grain.
These are examples of ways to incorporate more fiber-rich and plant-based foods. They should not be viewed as guaranteed sleep treatments.
Final takeaway
New research published in Nature Health found that higher fiber density, greater plant-food diversity and greater whole-plant food intake were associated with several measures of sleep physiology, including more deep and REM sleep and lower nighttime heart rate.
The research does not show that one food can fix poor sleep.
Instead, it adds to a growing body of evidence examining how overall dietary patterns may relate to sleep. Fiber-rich foods and a wider variety of minimally processed plant foods are areas researchers continue to investigate.
For more practical nutrition and wellness information, explore BrightSocialLife.
Medical Disclaimer
This article is for general educational purposes only and does not provide individualized medical advice. Health decisions should be discussed with a qualified healthcare professional.
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