Fibre

What is fibre and how does it work in the body?

Dietary fibre is a term that is used for carbohydrates found naturally in plants that the body cannot fully digest. It plays a key role in digestion, gut health and long-term disease prevention.

A high-fibre diet is linked with a lower risk of heart disease, type 2 diabetes and bowel cancer, based on large population studies reviewed by the UK Scientific Advisory Committee on Nutrition (SACN).

In the UK, adults are advised to eat 30g of fibre per day, but most people consume around 20g or less.

Fibre passes through the small intestine largely undigested and reaches the large intestine. Here, it can be fermented by gut bacteria and add bulk to stools.

This process helps regulate digestion but also produces compounds such as short-chain fatty acids, which may support gut health and reduce inflammation.

It is important to eat a variety of fibre-containing foods because different fibres have different effects in the body.

"In the UK, only around 4 in 100 adults meet the recommended fibre intake, so finding simple ways to include more fibre in everyday meals really matters."

Katerina Sakellaropoulou, Nutrition Scientist, British Nutrition Foundation

Why fibre matters for health

A large body of research shows that higher fibre intake is associated with better long-term health outcomes.

Heart health

Some fibres, particularly soluble fibres such as beta‑glucans, can help lower LDL (often called “bad”) cholesterol by reducing its absorption in the gut.

Blood sugar control

Fibre slows digestion, which helps reduce sharp rises in blood glucose after meals and supports better glycaemic control.

Digestive health

Some types of fibre, such as bran from wholegrains, increases stool bulk and helps prevent constipation, supporting normal bowel function.

Long-term disease risk

High-fibre diets are linked to a lower risk of:

Cardiovascular disease
Type 2 diabetes
Colorectal cancer

These findings are supported by large-scale reviews of epidemiological studies and clinical trials.

Foods rich in fibre: what to eat and why

Fibre is found in a wide range of plant foods, including wholegrains, pulses, fruit, vegetables, nuts and seeds.

These foods provide different types of fibre, which vary in how they affect digestion, cholesterol levels and the gut microbiome.

Evidence suggests that eating a variety of fibre-rich foods is more beneficial than relying on a single source.

Key dietary fibre sources:

Wholegrains (e.g. oats, barley, whole wheat)

Provide cereal fibres including cellulose, arabinoxylans and beta-glucans
Shown to improve gut function, reducing risk of constipation
Linked with improved cholesterol and heart health

Pulses (beans, lentils, chickpeas)

Provide fermentable fibres, such as oligosaccharides which are used for ‘food’ by beneficial gut bacteria
Support gut bacteria and blood sugar control

Fruit and vegetables

Provide a mix of fibre types including fermentable pectins and fructans, and insoluble types such as cellulose
Can have a range of health effects including supporting heart health, reducing risk of constipation and helping blood sugar control

Nuts and seeds

Provide a range of fibre types including fermentable oligosaccharides, soluble pectins and insoluble cellulose.
Can support satiety, help lower cholesterol and support gut health.

Resistant starch foods (e.g. cooled potatoes or pasta)

Act like fibre in the gut because the structure of these starches mean they cannot be digested
Feed beneficial bacteria and can support the microbiome

Sources of Fibre:

Food	portion size (g)	fibre per portion (g)	fibre per 100g
Starchy foods
Wholegrain pasta	180	8.8	4.9
Oats	45	3.5	7.8
Baked potato	220	4.6	2.1
Quinoa	180	6.3	3.5
Bran flakes	40	5.4	13.5
Wholemeal bread	80	5.8	7.3
Bulgur wheat	180	4.4	2.4
Fruit and veg
Berries	80	3.3	4.1
Banana	80	1.1	1.4
Apple	80	1.0	1.3
Pear	80	1.8	2.3
Spinach	80	1.0	1.3
Broccoli	80	1.1	1.4
Green beans	80	3.3	4.1
Carrots	80	3.1	3.9
Dates	30	3.0	10.0
Dried apricots	30	3.0	10.0
Protein foods
Pumpkin seeds	20	1.3	6.7
Sunflower seeds	20	1.6	8.0
Almonds	20	2.0	10.0
Lentils	120	8.1	6.8
Chickpeas	120	6.2	5.2
Red kidney beans	120	9.4	7.8
Baked Beans	200	8.5	4.3

Top 10 Sources Of Fibre

Our expert Dr Stacey Lockyer shares 10 of the best sources of fibre based on how easy they are to introduce into your existing diet.

Wholegrain breakfast cereals

Beans and pulses

jacket potatoes with filling, including spring onions, low fat cheese and ham loading=

Potatoes with skin

Nuts and seeds

Dried fruits

Wholewheat pasta

Wholegrain bread

Peas

Wholegrain crackers

Other wholegrains

Key facts about Fibre

Dietary fibre is a carbohydrate found naturally in plants.
Fibre helps to keep our digestive system healthy, maintain a healthy bodyweight and prevent constipation.
High fibre diets can help to prevent some diseases.
In the UK, most adults do not consume enough fibre so it’s important to understand how we can get more fibre into our diets.

10 Top Tips To Increase Your Fibre Intake

Remember, if you need to increase your fibre intake, it’s a good idea to make these changes gradually to avoid bloating and gas.

It’s also important to drink plenty of fluids (around 6-8 glasses per day for adults) and to be active for at least 150 minutes per week - as these both contribute to keeping your gut healthy.

Choose a high-fibre breakfast cereal - for example, wholegrain cereals like wholewheat biscuit cereal, no added sugar muesli, bran flakes or porridge.
Add fibre to your cereal - try adding fresh fruit, dried fruit, seeds and/or nuts to your cereal or yogurt.
Switch to wholemeal or seeded wholegrain breads - if you or your family usually only like white bread, start by trying the versions that combine white and wholemeal flours.
Cook with wholegrains - like wholewheat pasta, bulgur wheat or brown rice.
Leave the skin on potatoes - like baked potatoes, wedges or boiled new potatoes.
Snack on fibre-rich foods - try opting for snacks like fruit, vegetable sticks, rye crackers, oatcakes, houmous and unsalted nuts.
Include plenty of vegetables with meals - either as a side dish or added to sauces, stews or curries. This is a great way of getting children to eat more veg!
Stock up your freezer - keeping a handy supply of frozen vegetables in your freezer can prevent waste and ensure you’re never without.
Add pulses to your favourite meals - pulses like beans, lentils or chickpeas can be easily added to stews, curries and salads.
Don’t forget canned foods - canned beans or chickpeas are a quick and cost-effective way to add fibre to a meal.

Fibre FAQs

Does fibre increase the ‘good bacteria’ in our gut?

Although the science in this area is still at an early stage, it appears that having a diet rich in a variety of fibre may help to increase the ‘good’ bacteria in the gut.

It’s estimated that we have around 100 trillion micro-organisms in our gut (gut microbiota) and most of these are bacteria. There are many species of gut bacteria, and these can be either beneficial or harmful to our health. The balance of the bacteria in our gut can be affected by several different factors, including our diet and lifestyle.

Research is increasingly showing the importance of the bacteria in our gut when it comes to our health. Studies have investigated the effects of our gut bacteria on different aspects of our health including gut health (such as irritable bowel syndrome), obesity, immune function and brain function.

Fermentable fibres such as inulins from onions, leeks, wheat and oats and galacto-oligosaccharides, found in pulses like beans, lentils and chickpeas provide a food source for ‘good’ gut bacteria.

Can fibre cause bloating?

If you are not getting enough fibre in your diet and you quickly increase your intake, you may experience bloating whilst your digestive system gets used to the change.

You should aim to gradually introduce more fibre to allow the bacteria in your digestive system to adjust.

Can you have too much fibre?

Yes. Consuming excessive amounts of fibre can cause symptoms like bloating, cramping, constipation or diarrhoea and dehydration.

It can also prevent the absorption of some key nutrients.

Eating too much fibre can make you feel full, preventing you from consuming a variety of other foods. It's important to have a balanced diet so try to stick to the recommended amounts.

If you feel you are consuming too much fibre or suffering from the effects of too much fibre, you should seek medical and dietary advice from your GP.

Can fibre make irritable bowel syndrome (IBS) worse?

If you have been diagnosed with IBS, you may find that your symptoms worsen when you consume high fibre foods.

However, there is no one recommended diet or medication for those who suffer from IBS. You should consult with your GP who may recommend creating a food diary to better understand your triggers whilst also ensuring you are getting the fibre you need to stay healthy. You may also be referred to a dietitian to help you manage your symptoms and diet.

Examples of fibres

Fibres and the effects on our body

Cereal fibres - add bulk to stools and can help reduce constipation.

Beta glucans from oats and barley - can help control blood cholesterol.

Inulins from foods like bananas, onions and leeks provide food for gut bacteria.

You also might like to read about:

Starchy Foods

Starchy foods like bread, pasta and rice should make up about a third of the foods we eat. They are an important source of fibre, vitamins and minerals.

Hydration

Our bodies need water for many functions including regulating temperature, physical activity and brain function - so it’s important to drink the right amount

Vitamins and Minerals

Vitamins and minerals are essential nutrients which we must get from our diet.

More on dietary fibre

The fun way to fibre

Getting enough fibre can help reduce the risk of heart disease, type 2 diabetes, and bowel cancer.

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7 day meal planner

The British Nutrition Foundation has developed a 7-day meal plan for adults looking to meet recommendations on fibre

Find out more

Understanding food labels

Food labels provide a lot of useful information, provided you know where to look