Your sleep is influenced by a lot of factors, including your diet, lifestyle, stress and more. A new study suggests that what you eat during the day may impact how your body moves through different stages of sleep at night. The study published in Nature Health found that people who consumed more fibre relative to their total calorie intake spent slightly more time in deep and REM sleep, and less time in less sleep. The study also linked higher fibre intake with a lower average heart rate during sleep.

The study does not say that fibre is a cure for insomnia or that simply eating more fibre will guarantee better sleep. However, it does add to growing evidence that overall diet quality, plant-food intake and meal patterns may affect sleep physiology. Fibre is found naturally in fruits, vegetables, whole grains, legumes, nuts and seeds, making it possible to increase intake through everyday foods.

What Did The Study Find?

The study looked at the relationship between daily food choices and sleep. Researchers analysed 4,793 nights of dietary and sleep data from 3,598 predominantly healthy adults. Participants recorded what they ate in real time, while wearable devices tracked different stages of their sleep.

Researchers found that higher fibre density was associated with a small increase in restorative sleep. People consuming more fibre relative to their calorie intake spent about 0.59 percentage points more time in deep sleep and 0.76 percentage points more in REM sleep. They also spent about 1.35 percentage points less time in light sleep. Higher fibre intake was additionally linked to an average reduction of about 1.14 beats per minute in nighttime heart rate.

Why Is Deep Sleep Important?

Sleep is not one continuous state. During the night, the body moves through different stages, including light sleep, deep sleep and REM sleep.

Deep sleep is considered particularly restorative. During this stage, the body carries out important processes linked to physical recovery. REM sleep, meanwhile, is involved in brain functions such as memory and learning. Therefore, spending more time in these stages may be important for your sleep quality. However, the changes observed in the study were relatively small.

How Can Fibre Affect Sleep?

One possible explanation is fibre's effect on blood sugar. Fibre slows the absorption of glucose from food, which may help prevent sharp changes in blood sugar levels. Stable blood sugar during the night could reduce the body's response to a drop in blood glucose. Such a response can involve hormones such as adrenaline and cortisol and may increase heart rate, hunger or sweating, which could disturb sleep.

Fibre may also affect sleep through the gut microbiome. Gut bacteria breaks down certain types of fibre and produces compounds called short-chain fatty acids. These compounds may influence processes involved in nervous-system regulation and could be one pathway that connects diet, the gut and sleep.

Which Foods Are High In Fibre?

Fibre is naturally present in many plant-based foods. Some options include:

  • Fruits such as apples, pears, oranges and berries
  • Vegetables such as broccoli, carrots and green peas
  • Beans, chickpeas, lentils and other legumes
  • Whole grains such as oats, barley and whole-wheat products
  • Nuts and seeds
  • Chia seeds and flaxseeds

Eating a variety of plant foods may be useful. The study found that greater plant diversity and higher whole food intake were also associated with lower nighttime heart rate.

There is no established amount of fibre specifically required to improve sleep. Current dietary guidance generally recommends around 25 to 38 grams of fibre a day for adults, depending on factors such as age and sex.

The study also found that when people ate also influenced their sleep. Heavier meals in the six hours before bedtime was associated with about 7.7 additional minutes of total sleep, but also with a slightly higher nighttime heart rate. This suggests that sleeping for longer does not necessarily mean the sleep was better.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.