Soluble fibre
Dissolves or swells in water. Sources include oats, barley, legumes, fruit and vegetables.
Fibre, explained
What is fibre, and why is it helpful?
Fibre is a family of carbohydrates from plant foods that your small intestine does not fully break down. Different fibres hold water, add bulk or become food for microbes lower in the gut.
Last reviewed 24 August 2026 · General information, not medical advice
Plants
Where dietary fibre begins
3
Useful groups explained below
25 g
Adult women: adequate intake
30 g
Adult men: adequate intake
The short answer
Fibre is carbohydrate that takes a different route.
Most digestible carbohydrates are broken into smaller molecules and absorbed in the small intestine. Dietary fibre is not fully broken down there. Some continues largely intact, while other types are fermented by bacteria in the large intestine.
That is why “fibre” does not describe one ingredient or one effect. It covers many plant compounds with different structures and different physical or microbial jobs.
Healthdirect fibre guideThe main types
Three useful ways to understand fibre.
Foods usually contain a mixture, so these are practical groupings rather than three completely separate boxes.
Insoluble fibre
Does not dissolve in water. It is found in wholegrains, fruit and vegetable skins, nuts and seeds.
Resistant starch
Escapes digestion in the small intestine. Sources include beans, lentils, under-ripe bananas and cooked then cooled rice or potatoes.
Why it is helpful
Different fibres do different jobs.
Water and bulk
The water-holding and bulking properties of some fibres support normal stool form and regular bowel movements.
Microbial fermentation
Gut microbes can ferment some fibres and resistant starch, producing metabolites such as short-chain fatty acids. The response depends on the fibre and the microbial community.
Variety on the plate
Fibre-rich foods also bring other nutrients. Eating across legumes, wholegrains, fruit, vegetables, nuts and seeds provides more variety than relying on one source.
Food sources
Fibre appears across the plant-food aisle.
Exact amounts vary by variety, portion, preparation and brand. Packaged foods should be checked against their nutrition information panel.
| Food group | Everyday examples | Types represented |
|---|---|---|
| Legumes | Lentils, chickpeas, split peas and beans | Soluble, insoluble and resistant starch |
| Wholegrains | Oats, barley, brown rice and wholegrain bread | Soluble and insoluble fibre |
| Fruit | Berries, pears, apples, oranges and bananas | A mixture that varies by fruit and ripeness |
| Vegetables | Peas, broccoli, carrots, potatoes and leafy greens | A mixture that varies by plant and preparation |
| Nuts and seeds | Almonds, chia, flax and sunflower seeds | Mostly insoluble, with some soluble fibre |
Daily amount
Australian guidance uses 25 g and 30 g.
The Australian and New Zealand Nutrient Reference Values set an Adequate Intake of 25 g a day for adult women and 30 g a day for adult men. Individual needs can differ, and these figures describe total dietary fibre across the day.
A varied pattern matters as much as chasing one number. Healthdirect recommends fruit, vegetables including legumes, and wholegrain or wholemeal foods as the foundation.
Australian Nutrient Reference ValuesAdding more
Make the change gradual and repeatable.
A large overnight jump is not required to build a higher-fibre routine.
- Notice Check the foods you already eat and read nutrition information panels before deciding where a gap exists.
- Add Choose one repeatable change, such as legumes in one meal, wholegrain bread or fruit with breakfast.
- Build Increase fibre gradually so your usual eating pattern has time to adjust.
- Drink Fibre absorbs fluid, so include enough liquid, including water, as your fibre intake rises.
Common questions
Fibre, without the jargon.
Is fibre a carbohydrate?
Yes. Fibre is a broad group of carbohydrates from plants that are not fully broken down and absorbed in the small intestine.
Are fibre and fiber the same thing?
Yes. “Fibre” is the Australian and British spelling; “fiber” is the American spelling.
Is every type of fibre prebiotic?
No. Fibre is the broader category. “Prebiotic” is used more narrowly for substrates that are selectively used by particular microbes. Not every fibre meets that definition.
What foods are naturally high in fibre?
Legumes, wholegrains, fruit, vegetables, nuts and seeds are the main groups. A mix is useful because each food brings a different fibre profile.
Should fibre intake increase all at once?
No. Health guidance recommends increasing it gradually and drinking enough fluid. Seek personalised advice if a clinician has told you to limit fibre or you have a condition affecting your gut.
Sources
Check the guidance.
- Healthdirect Australia — High-fibre foods and diet healthdirect.gov.au/high-fibre-foods-and-diet
- Australian and New Zealand Nutrient Reference Values — Dietary fibre eatforhealth.gov.au/nutrient-reference-values/nutrients/dietary-fibre
- Makki et al., 2018 — Dietary fibre and the gut microbiota PubMed 29902436
- Gibson et al., 2017 — ISAPP consensus definition of a prebiotic PubMed 28611480
This page provides general nutrition information. It does not diagnose, treat or prevent a medical condition. For advice that accounts for your health, medicines or dietary restrictions, speak with a doctor or accredited practising dietitian.
A measured top-up
Five fibre sources.
One daily scoop.
Whole foods remain the foundation. BIOMEWARD combines five fibre sources as a convenient addition, with the ingredient research published for you to inspect.
See BIOMEWARD