Dietary Fibre: What’s all the Fuss about?
Nutrition trends come and go, but all the current fuss about fibre is one trend we can completely understand the hype around. It’s about time this powerhouse nutrient got the recognition it deserves!
But what exactly is dietary fibre, why is it so important for your gut and overall health, and how can you get more of it without completely overhauling your diet?
Let’s break it down.
What is dietary fibre?
Dietary fibre is a group of carbohydrates and other plant components that aren't fully digested and absorbed in the small intestine. Instead, different types of fibre travel through the digestive tract where they can have a range of effects.
Different fibres behave differently in the digestive tract. Some form gels and hold onto water, some add bulk to stool, and others are fermented by bacteria in the large intestine.
This means fibre isn't simply one thing — and there's no single "best" type of fibre.
Some fibres help keep bowel movements regular, some can influence blood glucose and cholesterol, and others provide food for the microorganisms living in your gut.
Eating a variety of plant foods helps you consume a variety of fibres, which is one reason why dietary diversity is so important for gut health.
Why is fibre important?
Fibre plays an important role in digestive health and is associated with a number of benefits for overall health.
Adequate fibre intake can help:
Support regular bowel movements
Prevent and manage constipation
Improve stool consistency
Support a healthy gut microbiome
Increase feelings of fullness after meals
Support healthy blood glucose regulation
Help maintain healthy cholesterol levels
Contribute to heart health
Reduce the risk of some chronic diseases
Despite these benefits, many Australians don't consume enough fibre.
How much fibre do you need each day?
According to the Australian and New Zealand Nutrient Reference Values, the Adequate Intake (AI) for adults is:
Women: 25 g per day
Men: 30 g per day
Fibre requirements vary across different life stages, including during pregnancy and breastfeeding.
Rather than becoming fixated on a single number, think about fibre as something to build into your overall eating pattern. A diet containing plenty of vegetables, fruit, wholegrains, legumes, nuts and seeds will naturally help you work towards your fibre needs.
What are the different types of fibre?
You may have heard fibre described as soluble or insoluble.
This traditional classification is still used in nutrition, but it doesn't always tell us very much about how a particular fibre actually behaves in the gut.
A more useful way to think about fibre is by its functional properties — what it does once it reaches your digestive system.
Different fibres can have:
Gelling properties – hold onto water and form a gel
Bulking properties – add bulk to stool and support bowel regularity
Fermentable properties – can be broken down by gut bacteria and contribute to gut microbiome activity
Many foods contain a combination of different fibres, and a single fibre can have more than one of these properties. These categories therefore aren't completely separate — they help us understand the different ways fibre can behave in the gut.
Let's take a closer look.
Gelling Fibre
Gelling fibres absorb water and form a gel-like substance in the digestive tract.
This can slow digestion, influence how quickly carbohydrates are absorbed and help regulate stool consistency.
Gelling fibres can be particularly useful for bowel health. Depending on the individual and the specific fibre, they may help soften hard stools or improve the consistency of loose stools.
One of the best-known examples is psyllium husk, which absorbs water and forms a viscous gel.
Foods providing gelling fibre
Psyllium husk
Oats and oat bran
Barley
Chia seeds
Flaxseeds (linseeds)
Kiwifruit
Legumes such as lentils, chickpeas and beans
What can gelling fibre do?
Depending on the specific fibre, it can:
Help regulate stool consistency
Support bowel regularity
Slow digestion
Help moderate blood glucose responses
Increase feelings of fullness
Help lower LDL cholesterol
Tip: If you're increasing gelling fibre, make sure you're also getting enough fluid. Psyllium in particular should be taken with adequate fluid.
Bulking Fibre
Bulking fibres increase the volume and/or water-holding capacity of stool.
This can help support movement through the digestive tract and promote regular bowel movements.
Bulking fibres are often associated with the idea of "roughage". They can be particularly useful for people who struggle with constipation, although simply adding large amounts of fibre isn't always the best approach if you have ongoing digestive symptoms.
Foods providing bulking fibre
Wholegrain breads and cereals – wholemeal bread, grainy bread, wholegrain breakfast cereals and wheat biscuits
Wheat bran – bran cereals and foods containing added wheat bran
Fruit skins – apples, pears, peaches and plums
Vegetable skins – potatoes, sweet potatoes and carrots
Vegetables – broccoli, cauliflower, cabbage, green beans and Brussels sprouts
Wholegrains – brown rice, barley, bulgur and wholegrain pasta
Nuts – almonds, peanuts, walnuts and pistachios
Seeds – sunflower seeds, pumpkin seeds, sesame seeds and flaxseeds
Legumes – chickpeas, kidney beans, cannellini beans, black beans, lentils and split peas
What can bulking fibre do?
Add bulk to stool
Support regular bowel movements
Help prevent constipation
Contribute to overall digestive health
It's worth remembering that most whole plant foods contain a mixture of different fibres, rather than fitting neatly into one category.
And more isn't necessarily better. For some people with IBS, suddenly increasing large amounts of coarse or poorly tolerated fibre can worsen bloating, abdominal discomfort or changes in bowel habits.
Fermentable Fibre
Fermentable fibres can be broken down by bacteria in the large intestine.
Our digestive enzymes can't fully break down these fibres, so they reach the colon where they can be fermented by gut microorganisms.
When bacteria ferment fibre, they produce compounds including short-chain fatty acids (SCFAs) such as acetate, propionate and butyrate. These fibres play important roles in the gut and are one of the ways our diet interacts with the gut microbiome.
Foods providing fermentable fibre
Legumes – beans, chickpeas, lentils and split peas
Wholegrains – oats and barley
Fruit – apples, pears and some stone fruits
Slightly green bananas – a source of resistant starch
Cooked and cooled potatoes – a source of resistant starch
Cooked and cooled rice and pasta – a source of resistant starch
Onion and garlic – sources of fructans
Some nuts and seeds
Some fermentable fibres are also considered prebiotics. However, not all fermentable fibre meets the definition of a prebiotic.
Prebiotics are substances that are selectively utilised by microorganisms and provide a health benefit. Examples include inulin and fructans, GOS (galacto-oligosaccharides) and some forms of resistant starch.
These compounds occur naturally in foods such as legumes, onions, garlic, some fruits and vegetables, oats and cooked-and-cooled starchy foods.
While prebiotic fibres can support the gut microbiome, they can also increase gas and bloating in some people, particularly when intake is increased quickly. If you have IBS, the amount and type of fermentable fibre may be particularly important.
What can fermentable fibre do?
Fermentable fibre can:
Provide a substrate for gut microorganisms
Support microbial activity
Contribute to the production of short-chain fatty acids
Support the health and function of the large intestine
Contribute to a diverse gut microbiome
It's important to remember that fermentable doesn't automatically mean "better". Some highly fermentable fibres can cause increased gas and bloating, particularly when intake is increased quickly or in people with certain gastrointestinal conditions. The type, amount and individual tolerance all matter.
How to Increase Fibre Without the Bloating
If you're currently eating very little fibre, don't suddenly jump from 10 g to 30 g overnight!
A rapid increase can cause bloating, gas, abdominal discomfort or changes in bowel habits, particularly if your gut isn't used to a higher fibre intake.
Instead:
Increase fibre gradually
Introduce new high-fibre foods in smaller amounts
Spread fibre throughout the day
Drink enough fluid
Pay attention to how your body responds
If you have IBS or another gastrointestinal condition, the type of fibre you choose can be just as important as the amount.
For example, some rapidly fermentable fibres can increase gas and bloating, while gel-forming fibres such as psyllium may be better tolerated by some people.
This is why personalised nutrition advice can be particularly useful when digestive symptoms are involved.
The Bottom Line: Why Fibre Matters
Fibre is much more than simply a nutrient that "keeps you regular".
It can support bowel function, gut microbiome health, blood glucose regulation, cholesterol levels and long-term health.
The best way to increase your fibre intake isn't to focus on one particular fibre supplement or "superfood". Instead, aim for variety.
Include a mixture of:
🌾 Wholegrains
🥕 Vegetables
🍎 Fruit
🫘 Legumes
🥜 Nuts and seeds
Different plant foods provide different combinations of gelling, bulking and fermentable fibres, so eating a diverse range of plant foods is a simple way to support a diverse range of functions in your gut.
And remember — fibre should be part of your diet, not something you need to obsess over.
When Should You See a Dietitian About Fibre?
If you're experiencing ongoing digestive symptoms or struggling to meet your fibre needs, an Accredited Practising Dietitian (APD) can help you work out what approach is right for you.
You may benefit from personalised nutrition advice if you:
Experience ongoing bloating, abdominal discomfort or changes in bowel habits
Struggle with constipation or loose stools
Want to increase your fibre intake but find that high-fibre foods worsen your symptoms
Have IBS or another gastrointestinal condition
Are unsure which fibre-rich foods are right for you
Want practical strategies to improve your overall diet and gut health
APDs are university-trained nutrition professionals who provide evidence-based, individualised nutrition advice based on your health needs, lifestyle, preferences and goals.
At Eatwise Dietetics, we take a practical and individualised approach to nutrition. Whether you're looking to improve your gut health, manage digestive symptoms or simply feel more confident about what you're eating, we're here to help.
Ready to make fibre work for you? Book a consultation with Eatwise Dietetics for personalised nutrition support.