Initial publication date: 25 April 2026
Last reviewed: 25 April 2026
Next review due: 25 April 2027
Nutrition trends come and go, but fibre is one trend worth paying attention to. From keeping your bowel movements regular to supporting heart health and feeding your gut microbes, fibre does a lot more than you might think.
But what exactly is dietary fibre? Are some types better than others? And how can you eat more fibre without feeling bloated all the time?
Let's break down what the research tells us — and how to put it into practice.
What is dietary fibre?
Dietary fibre is a broad group of carbohydrates that resist digestion and absorption in the small intestine. Instead of being completely broken down like other carbohydrates, different types of fibre move through the digestive tract, where they can have a range of effects.
Some fibres hold onto water and form a gel. Others contribute to stool bulk, while some are fermented by microorganisms in the large intestine. Many fibres have more than one of these properties. [1,2]
This is important because fibre isn't one single substance, and different types can have different effects on your body.
Some fibres help regulate bowel movements, certain viscous fibres can help lower LDL cholesterol, and fermentable fibres provide substrates that gut microorganisms can use. The benefits depend on the type of fibre, the amount consumed and the individual.
One of the simplest ways to obtain a range of fibres is to eat a variety of plant foods, including vegetables, fruit, wholegrains, legumes, nuts and seeds.
Why is fibre important?
Fibre has a well-established role in bowel health, but its benefits extend beyond keeping you regular.
Depending on the type of fibre and your overall diet, adequate intake can help:
Support regular bowel movements and stool consistency.
Prevent or manage some forms of constipation.
Support gut microbial activity and the production of short-chain fatty acids.
Help regulate blood glucose responses after meals.
Lower LDL cholesterol when consuming certain viscous fibres.
Contribute to heart and metabolic health.
Support a dietary pattern associated with a lower risk of several chronic diseases. [1,3]
A large series of systematic reviews and meta-analyses found that higher dietary fibre intake was associated with lower risks of several non-communicable diseases and lower mortality. However, these findings relate to overall dietary fibre intake and patterns; they don't mean every fibre supplement will produce the same benefits. [3]
Despite these benefits, many people don't meet recommended fibre intakes.
How much fibre do you need each day?
The Australian and New Zealand Nutrient Reference Values provide the following Adequate Intakes (AIs) for adults: [4]
Women: 25 g per day
Men: 30 g per day
Requirements differ during pregnancy and breastfeeding. For example, the AI is 28 g per day during pregnancy and 30 g per day during lactation for adults aged 19–50 years. Recommendations also vary for children and adolescents.
An AI is a reference value for population nutrition, rather than a precise threshold that determines whether an individual's diet is adequate.
Instead of becoming fixated on hitting an exact number every day, focus on including fibre-rich foods regularly and building variety into your usual eating pattern.
Are there different types of fibre?
You may have heard fibre described as soluble or insoluble. These terms describe whether a fibre dissolves in water, but they don't fully explain how it behaves in the digestive tract.
For example, psyllium and inulin can both dissolve in water, yet they behave differently: psyllium forms a viscous gel, while inulin is readily fermented by gut bacteria.
For understanding fibre's effects on gut health, it can be more useful to consider its functional properties — what it does once it reaches the digestive system. [1,2]
Three useful properties to understand are:
Gelling or viscous: forms a gel and holds onto water.
Bulking: increases stool mass or water content.
Fermentable: can be broken down by microorganisms in the large intestine.
These categories overlap. A single fibre can have several properties, and whole plant foods usually contain a mixture of different fibres.
1. Gelling and viscous fibre
Gelling fibres absorb water and form a gel-like substance in the digestive tract. Depending on the fibre, this can influence stool consistency, digestion and the absorption of nutrients.
Some viscous fibres can slow the absorption of glucose after a meal. Certain types, including psyllium and beta-glucan from oats and barley, can also help lower LDL cholesterol when consumed in appropriate amounts. [1,2]
Foods and sources include:
Psyllium husk.
Oats and oat bran.
Barley.
Chia seeds.
Flaxseeds (linseeds).
Some fruits, vegetables and legumes, which contain gel-forming fibres such as pectin.
Psyllium is particularly useful to know about because it absorbs water and forms a gel that can help regulate stool consistency. Clinical guidelines also support its use for improving overall symptoms in some people with IBS. [5]
What can gelling fibre do?
Depending on the specific fibre, it may help:
Soften hard stools and improve stool consistency.
Support bowel regularity.
Moderate post-meal blood glucose responses.
Lower LDL cholesterol.
Increase feelings of fullness.
A practical tip: If you're using psyllium, follow the product directions and take it with adequate fluid. Start with a small amount and increase gradually if appropriate. Psyllium isn't suitable for everyone, particularly people with swallowing difficulties or certain intestinal conditions, so seek advice if you're unsure.
2. Bulking fibre
Bulking fibres increase the volume and/or water-holding capacity of stool. This can help support bowel movements, although the effect depends on the fibre's properties and the individual's circumstances.
Some less-digestible plant structures, including cellulose, contribute to stool bulk. Wholegrain foods, vegetables, fruit, legumes, nuts and seeds provide different combinations of fibres that can support bowel function. [1,2]
Foods that contribute bulking fibre include:
Wholegrain breads and cereals.
Bran-based cereals.
Brown rice, barley and quinoa.
Vegetables and edible vegetable skins.
Fruit and edible fruit skins.
Legumes.
Nuts and seeds.
These foods aren't exclusively sources of bulking fibre. Many also contain fermentable or gel-forming fibres.
What can bulking fibre do?
Depending on the type and amount consumed, it may help:
Increase stool bulk.
Support regular bowel movements.
Contribute to the management of constipation.
Support overall digestive health.
It's worth remembering that more fibre isn't always better, particularly when digestive symptoms are involved. Increasing large amounts of coarse bran or other poorly tolerated fibres can worsen bloating and abdominal discomfort in some people, including those with IBS.
If constipation is ongoing, the best approach depends on its cause. Simply adding more bran or fibre may not resolve every type of constipation.
3. Fermentable fibre
Fermentable fibres reach the large intestine, where gut microorganisms can break them down. This process is called fermentation.
One of the products of fermentation is a group of compounds known as short-chain fatty acids (SCFAs), including acetate, propionate and butyrate. These compounds have several roles in the gut and interact with the cells lining the intestine and the wider host environment. Butyrate, for example, is an important energy source for cells lining the colon. [1,2]
Fermentable fibre is one way our diet interacts with the gut microbiome, but the effects depend on the type of fibre and the microbial community present.
Foods providing fermentable fibre include:
Legumes, such as beans, lentils and chickpeas.
Some fruits, including apples, pears and certain stone fruits.
Onions, garlic and other foods containing fructans.
Slightly green bananas, which can provide resistant starch.
Cooked and cooled potatoes, rice and pasta, which can contain resistant starch.
Some wholegrains, nuts and seeds.
The amount and type of fibre vary between foods and depend on factors such as variety, ripeness, processing and cooking method.
Is fermentable fibre the same as a prebiotic?
Not exactly.
A prebiotic is a substrate that is selectively utilised by host microorganisms and confers a health benefit. This means not every fermentable fibre automatically qualifies as a prebiotic. [6]
Examples of recognised prebiotic substrates include certain inulin-type fructans, galactooligosaccharides (GOS) and some forms of resistant starch.
Prebiotics can influence microbial activity, but this doesn't mean that increasing every type of fermentable fibre will improve symptoms or produce the same health effects.
Can fermentable fibre cause bloating?
Yes — and this is where individual tolerance matters.
Fermentation can produce gas. For many people, this is a normal part of digestion, but in people with IBS or visceral hypersensitivity, gas and changes in intestinal contents may contribute to bloating, pain or discomfort.
Some rapidly fermented fibres, including inulin, fructooligosaccharides (FOS) and galactooligosaccharides (GOS), can aggravate symptoms in some people with IBS. Others, including psyllium, may be better tolerated by many people. However, tolerance varies and no single fibre suits everyone. [5,7]
Fermentable doesn't automatically mean better or worse. The type, dose, rate of increase and your individual response all matter.
How can you increase fibre without the bloating?
If you're currently eating very little fibre, jumping from 10 g to 30 g overnight probably isn't the most comfortable strategy.
A rapid increase can cause gas, bloating, abdominal discomfort or changes in bowel habits, particularly if your usual intake is low.
Instead, try these practical steps:
Increase gradually. Add one or two fibre-rich foods at a time rather than changing everything at once.
Spread fibre throughout the day. Include fibre at breakfast, lunch, dinner and snacks rather than relying on one very high-fibre meal.
Drink enough fluid. Fluid helps fibre do its job, particularly when increasing intake or using supplements such as psyllium.
Choose a variety of foods. Different plant foods provide different fibres and nutrients.
Pay attention to tolerance. If a particular food consistently triggers symptoms, adjust the portion or consider an alternative rather than assuming all fibre will cause the same response.
For example, you could add oats to breakfast, include fruit as a snack, choose wholegrain bread at lunch and add lentils or beans to a meal during the week.
If you have IBS or another gastrointestinal condition, the type of fibre can be just as important as the total amount. Psyllium may be a useful option for some people with IBS, while bran or highly fermentable fibres may worsen symptoms in others. [5,7]
If symptoms are persistent, it's worth seeking personalised advice rather than continuing to increase fibre without a plan.
The bottom line: why fibre matters
Fibre is much more than a nutrient that "keeps you regular". It contributes to bowel function, influences gut microbial activity and, depending on the type, can support blood glucose regulation and healthy cholesterol levels.
The best approach isn't to focus on one particular fibre supplement or so-called superfood. Instead, aim for variety, consistency and individual tolerance.
Include a mixture of:
Wholegrains.
Vegetables.
Fruit.
Legumes.
Nuts and seeds.
Different plant foods provide different combinations of fibres, so variety helps you access a broader range of fibre types and other nutrients.
And remember — fibre should be part of your diet, not something you need to obsess over.
When should you see a dietitian about fibre?
An Accredited Practising Dietitian (APD) can help you find an approach that suits your nutritional needs, symptoms and lifestyle.
You may benefit from personalised advice if you:
Experience ongoing bloating, abdominal discomfort or changes in bowel habits.
Struggle with constipation or loose stools.
Find that high-fibre foods worsen your symptoms.
Have IBS or another gastrointestinal condition.
Are unsure how to increase fibre without compromising your comfort.
Want to improve your overall diet and gut health.
At Eatwise Dietetics, we take a practical, individualised approach to nutrition. Whether you're looking to improve your gut health, manage digestive symptoms or feel more confident about what you're eating, we're here to help.
Ready to make fibre work for you? You can find an Accredited Practising Dietitian through Dietitians Australia or book an appointment with Eatwise Dietetics for personalised nutrition support.
Want to know more?
Increasing dietary fibre | NEMO Gastroenterology Group, Queensland Health
Fibres for your gut: sorting through the roughage | Dietitians Australia
References
Stephen AM, Champ MMJ, Cloran SJ, et al. Dietary fibre in Europe: current state of knowledge on definitions, sources, recommendations, intakes and relationships to health. Nutr Res Rev. 2017;30(2):149–190. https://doi.org/10.1017/S095442241700004X
Augustin LSA, Aas AM, Astrup A, et al. Dietary Fibre Consensus from the International Carbohydrate Quality Consortium (ICQC). Nutrients. 2020;12(9):2553. https://doi.org/10.3390/nu12092553
Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019;393(10170):434–445. https://doi.org/10.1016/S0140-6736(18)31809-9
National Health and Medical Research Council and New Zealand Ministry of Health. Nutrient Reference Values for Australia and New Zealand: Dietary Fibre. https://www.eatforhealth.gov.au/nutrient-reference-values/nutrients/dietary-fibre
Moayyedi P, Quigley EMM, Lacy BE, et al. The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis. Am J Gastroenterol. 2014;109:1367–1374. https://doi.org/10.1038/ajg.2014.195
Gibson GR, Hutkins R, Sanders ME, et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol. 2017;14:491–502. https://doi.org/10.1038/nrgastro.2017.75
Collins L, Iacovou M. Fibre supplements and IBS. Monash FODMAP. https://www.monashfodmap.com/blog/fibre-supplements-ibs/
Acknowledgement of Country
Eatwise Dietetics acknowledges the Traditional Custodians of the lands on which we live and work. We honour their deep and ongoing connections to Country, lands, waters, culture and community. We pay our respects to Elders past and present and recognise the importance of Indigenous knowledge in caring for Country and sustaining food systems for future generations.