The importance of fibre for gut health and weight loss

Fibre is an important part of a healthy, balanced diet, yet many people do not eat enough of it. Found naturally in a wide variety of plant-based foods, fibre plays a key role in digestion, gut health, weight maintenance and overall wellbeing.

You’ve probably heard about the importance of fibre, but what is it and why should you be watching your fibre intake?

In this guide, we'll explain why fibre is important, its health benefits, how much you need each day and the best high-fibre foods to include in your diet.

What Is fibre?

Fibre is a type of carbohydrate found in plant-based foods that the body cannot fully digest.

Unlike other carbohydrates, fibre is not fully broken down and absorbed by the body. Instead, it passes through the digestive system, helping move food through the gut and supporting healthy bowel function.

For example, fibre can help to soften stools, which can relieve constipation, but it can also help to bulk up stools and make them firmer if you suffer from diarrhoea. This becomes especially important if you’re on weight loss medication, as both diarrhoea and constipation are common side effects.

There are two main types of fibre – soluble and insoluble, both of which play important roles in staying healthy.

Insoluble Fibre

Insoluble fibre does not dissolve in water and passes through the digestive system mostly unchanged.

Its main role is to add bulk to stools and help food move through the digestive tract more efficiently. Eating foods rich in insoluble fibre can help prevent constipation and support regular bowel movements.

Foods rich in insoluble fibre include:

• wholemeal bread
• brown rice
• wholegrain cereals
• wheat bran
• nuts and seeds
• many fruits and vegetables, particularly their skins

Soluble Fibre

Soluble fibre dissolves in water to form a gel-like substance in the digestive system. This can help slow digestion, helping you feel fuller for longer after eating.

Soluble fibre is fermented by gut bacteria, helping to support a healthy gut microbiome. It also helps to promote the growth of some of the “good” bacteria in your gut, which can have positive effects on the rest of your health.

In addition to this, it can also help to stabilise blood glucose levels, which is particularly helpful for those with type 2 diabetes mellitus or those at risk of developing it.

Foods rich in soluble fibre include:

• oats
• barley
• beans
• lentils
• peas
• pulses
• chickpeas
• fruit such as apples, pears, and citrus fruits
• vegetables such as carrots and sweet potatoes

Why do we need fibre in our diet?

Fibre is important because it:

• supports healthy digestion
• helps prevent constipation
• supports gut bacteria
• helps control blood sugar levels
• may reduce cholesterol levels
• helps you feel fuller for longer

Despite having plenty of benefits, some people with certain medical conditions, such as some types of irritable bowel syndrome (IBS), may be advised to avoid insoluble fibre as it may worsen their symptoms such as diarrhoea.

If you aren’t sure whether or not you should add more fibre to your diet, you should speak to your doctor or perhaps a dietitian in order to find out what would be best for you.

Health benefits of fibre

As mentioned, fibre plays a key role in supporting the ‘good bacteria’ in the gut, but it also helps you manage your sugar levels and feel fuller after meals, on top of lowering the risk of long-term disease.

Digestive health

One of fibre's most well-known benefits is its role in supporting healthy digestion. Insoluble fibre adds bulk to stools and helps food move more easily through the digestive tract, reducing the likelihood of constipation

Maintaining regular bowel movements is important for digestive comfort and your overall gut health.

Gut health

Certain types of fibre act as prebiotics, meaning they provide food for the beneficial bacteria living in your gut. These bacteria help keep your digestive system healthy and support regular digestion, bowel health, and normal immune function. Eating a variety of fibre-rich foods may help increase the diversity of beneficial gut bacteria, which is associated with better overall gut health.

Including a range of wholegrains, fruit, vegetables, beans, pulses, nuts and seeds in your diet can help support a healthy balance of gut bacteria and keep your digestive system functioning normally.

Heart health

Eating enough fibre as part of a healthy diet may help support heart health and healthy cholesterol levels. With high cholesterol, fats and other substances can build up in the blood, which can increase the risk of heart attacks and strokes. Soluble fibre may help reduce cholesterol levels by binding to cholesterol-containing substances in the digestive system and helping remove them from the body.

Blood sugar management

Because soluble fibre slows digestion, it can help slow the absorption of sugar into the bloodstream. This can help support more stable blood sugar levels after eating.

Weight management

Fibre-rich foods often take longer to eat and digest. They can also increase feelings of fullness, which may help you reduce your overall calorie intake.

Many foods naturally high in fibre, such as vegetables, fruits, beans, and wholegrains, are also nutrient-dense and filling, making them valuable additions to a balanced weight management plan.

Lower risk of disease

Eating enough fibre is associated with a range of health benefits and may contribute to a lower risk of certain long-term health conditions when included as part of a healthy lifestyle, such as:

• type 2 diabetes
• cardiovascular disease
• colorectal cancer

While fibre alone cannot prevent disease, including a variety of fibre-rich foods as part of a healthy lifestyle may contribute to better long-term health overall.

Does fibre make you lose weight?

Fibre can help you lose weight as part of a balanced diet, particularly soluble fibre found in foods such as oats, peas, beans and lentils because it helps slow digestion and promote feelings of fullness after eating.

While fibre shouldn't be the only focus of your diet, many people in the UK are not getting the recommended 30g of fibre per day. Increasing your intake can be a simple way to support both your digestive health and overall wellbeing.

Small changes can make a big difference. For example, you could start the day with a bowl of porridge, or add beans and lentils to meals such as curries, soups and pasta sauces to boost your fibre intake.

Many high-fibre foods are also affordable and versatile. Ingredients such as oats, beans and lentils can help bulk out meals, making them more filling and potentially helping your food budget go further.

If you're using semaglutide, increasing your fibre intake may help complement the medication's effects. Both soluble fibre and semaglutide can help you feel fuller for longer, which may make it easier to manage portion sizes, reduce cravings and avoid unnecessary snacking between meals. You can learn more about how these treatments work in our guide to Wegovy (Semaglutide).

Or, if you’re wondering which treatment options may be suitable for you, take a look at our treatment plans.

How much fibre should you eat per day?

Adults are recommended to consume around 30g of fibre per day as part of a healthy, balanced diet. However, people across the UK usually only eat 18g of fibre daily, so most of us should increase our intake.

If you’re planning on adding more fibre to your diet, you should make sure that you do it gradually to avoid any cramping or issues with your stools. Rapidly increasing the amount of fibre that you eat can end up making you feel poorly, so it’s best to make small changes every so often.

While most of us may not be eating the ideal amount of fibre, it’s fairly easy to incorporate more of it into your diet by making small changes or adding an extra portion of fruit or vegetables to a meal each day. As a guide, that can be as easy as having an extra side of vegetables with your lunch or dinner, some fruit and nuts for snacks, and generally including wholegrains, pulses, nuts or seeds throughout the day.

It's also important to drink plenty of water, as fibre works best when combined with adequate fluid intake.

Foods high in fibre

Some foods contain particularly high amounts of fibre and can help you reach your daily target more easily. Including a variety of these foods throughout the week can help you increase your fibre intake without making dramatic changes to your diet.

Good sources of fibre include:

Wholegrains

• wholemeal bread
• brown rice
• wholegrain breakfast cereals
• oats

Pulses

• lentils
• chickpeas
• beans
• peas

Fruit and vegetables

• pears
• apples
• berries
• broccoli
• brussels sprouts
• sweet potatoes

Nuts and seeds

• chia seeds
• flaxseeds
• almonds
• walnuts

Generally, the more ripe a fruit or vegetable is, the more soluble fibre it will contain (though you must remember that this can also increase the glycaemic index of certain foods). One good thing about fibre-rich foods is that they’re readily available in supermarkets, easy to incorporate int your diet and incredibly versatile.

If you need inspiration for your next meal, we have a variety of delicious high-fibre recipes in store for you, developed by our partner nutritionist Lisa Marley.

Signs you may not be eating enough fibre

If you're not eating enough fibre, you may notice some changes in your digestion and appetite.

Signs you may not be eating enough fibre include:

• constipation
• bloating
• feeling hungry shortly after meals
• irregular bowel movements
• difficulty maintaining a healthy weight

If you regularly experience digestive symptoms, speak to a healthcare professional for personalised advice.

How to increase your fibre intake

Increasing your fibre intake doesn't have to happen overnight. Small, sustainable changes to your daily eating habits can make a big difference over time. Here are 10 simple tips:

1. Swap white pasta and bread to wholemeal or wholegrain options.
2. Swap refined cereals for high-fibre options such as porridge oats.
3. Bulk out your meals by adding beans, lentils or chickpeas to soups, salads and stews.
4. Leave edible fruit and vegetable skins on where possible, such as apples, pears, sweep potatoes or even (controversially!) kiwis.
5. Snack on nuts and seeds. However, if you’re trying to lose weight, be mindful that they can be high in calories, and a few handfuls throughout the day can add up quickly!
6. Add berries to your breakfast. This can be a porridge or yoghurt bowl with an added handful of raspberries or blueberries.
7. Include vegetables with every meal.
8. Try chia or flaxseeds in yoghurt and smoothies.
9. Replace some refined carbohydrates with pulses.
10. Increase fibre gradually and drink plenty of water.

Small changes over time will add up

Fibre can support your gut health, digestion and weight management, but you don’t need to overhaul your whole diet overnight. Simple changes, like choosing wholegrains, adding beans or lentils to meals, or including an extra portion of fruit or vegetables, can help you gradually work towards your daily fibre needs.

Increase your intake at a pace that feels comfortable, keep well hydrated, and focus on variety. It’s the small, sustainable habits you can stick with that matter most.

“Fibre can be particularly helpful when you’re losing weight, as it supports healthy digestion and can help you feel fuller after eating. If you’re taking weight loss medication, build your fibre intake up gradually, especially if you’re already experiencing digestive side effects.”

Ayesha BashirPrescribing Pharmacist

Sources

• Fibre (2026) British Dietetic Association. [Accessed 7 October 2026]
• Fibre (2026) British Nutrition Foundation. [Accessed 7 October 2026]
• Dietary Fiber Intake and Gut Microbiota in Human Health (2022) PMC. [Accessed 7 October 2026]
• Dietary fiber and prebiotics and the gastrointestinal microbiota (2017) PubMed. [Accessed 7 October 2026]
• Carbohydrate quality and human health: a series of systematic reviews and meta-analyses (2019) PubMed. [Accessed 7 October 2026]
• How to get more fibre into your diet (2026) NHS. [Accessed 7 October 2026]