Quick answer: Dietary fibre (or “fiber”) is the part of plant foods your body can’t digest — and it’s one of the most consistently health-protective nutrients in the human diet. Research links higher fibre intake with better digestion and regularity, a more diverse gut microbiome, healthier cholesterol and blood-sugar responses, and a lower long-term risk of heart disease, type 2 diabetes and bowel cancer.12 Yet most Australian adults fall short of the recommended 25–30g a day.34
Key takeaways
- Fibre comes in three useful forms: soluble, insoluble and prebiotic (and many fibres are more than one).
- Adults should aim for about 25g/day (women) and 30g/day (men) — most of us get well under that.3
- The strongest evidence is for digestive health, the gut microbiome, heart health and blood-sugar control, with population studies also showing lower disease risk at higher intakes.12
- The gentlest way to add fibre is gradually, with variety and plenty of water — especially if you have a sensitive gut.
What is dietary fibre?
Dietary fibre is the group of carbohydrates in plant foods — vegetables, fruit, legumes, whole grains, nuts and seeds — that resist digestion in the small intestine and pass through to the large intestine (colon).5 Instead of being absorbed for energy, fibre does its work physically (adding bulk, holding water, forming gels) and biologically (feeding the bacteria in your gut).
There are three practical ways to think about fibre:
| Type | What it does | Found in |
|---|---|---|
| Soluble fibre | Dissolves in water and forms a gel; slows digestion, helps soften stool, can bind cholesterol | Oats, barley, legumes, apples, citrus, psyllium |
| Insoluble fibre | Adds bulk and helps move waste through the gut | Wholegrains, wheat bran, nuts, seeds, vegetable skins |
| Prebiotic fibre | Selectively fermented by beneficial gut bacteria as “food”6 | Onion, garlic, legumes, oats, chicory, partially hydrolysed guar gum |
Most whole foods contain a mix, which is exactly why fibre diversity matters more than any single type.7
How much fibre do you need per day?
In Australia and New Zealand, the Adequate Intake (AI) for dietary fibre is 25g/day for women and 30g/day for men.3 There’s also a higher “suggested dietary target” linked to reducing chronic-disease risk. The reality, though, is a gap: research shows most Australian adults don’t meet even the Adequate Intake, with only around a quarter to a third reaching it.4
| Group | Daily fibre target (Adequate Intake) |
|---|---|
| Women (19–50) | 25g |
| Men (19–50) | 30g |
| Pregnant women | 28g |
| Children | Lower, increasing with age |
If you’re starting well below target, you don’t need to hit the number overnight — building up gradually is both more comfortable and more sustainable (more on that below).
The science-backed benefits of fibre
1. Better digestion and regularity
This is the most established benefit. Fibre adds bulk and holds water, which softens stool and helps it move through the gut — supporting comfortable, regular bowel movements.57 In food-standards terms, “dietary fibre contributes to regular laxation” is a recognised, evidence-based effect of fibre.
2. It feeds your gut microbiome
Your colon is home to trillions of bacteria, and fibre is their primary fuel. When gut bacteria ferment fibre, they produce short-chain fatty acids (SCFAs) such as butyrate — a key energy source for the cells lining your gut and an important signalling molecule for the body.8 A more varied fibre intake is associated with a more diverse microbiome, which is considered a hallmark of gut resilience.7
3. Heart health
Higher fibre intakes — particularly viscous, soluble fibres — are associated with lower LDL (“bad”) cholesterol and reduced cardiovascular risk.19 A landmark series of systematic reviews and meta-analyses in The Lancet found that people with the highest fibre intakes had significantly lower rates of coronary heart disease and cardiovascular mortality compared with the lowest.1
4. Steadier blood sugar
Soluble and viscous fibres slow the rate at which sugars are absorbed, which can blunt blood-glucose spikes after meals.59 At a population level, higher fibre intake is linked with a meaningfully lower risk of developing type 2 diabetes.1
5. Appetite, fullness and healthy weight
Gel-forming fibres slow digestion and promote a feeling of fullness, which can help with appetite regulation as part of a balanced diet.69 Higher-fibre diets are consistently associated with healthier body weight over time.1
6. Lower long-term disease risk
Bringing it together: umbrella reviews and large meta-analyses link higher dietary fibre intake with lower risk of heart disease, type 2 diabetes, stroke and colorectal (bowel) cancer, along with lower all-cause mortality.12 These are population-level associations from observational research — not a promise for any individual — but the consistency of the evidence is part of why dietary guidelines worldwide encourage more fibre.
Soluble vs insoluble vs prebiotic fibre: which is best?
There’s no single “best” fibre — they do different jobs, and a healthy gut benefits from all three.7 Soluble and viscous fibres are the stars for cholesterol and blood sugar; insoluble fibre is great for bulk and regularity; prebiotic fibres feed your beneficial bacteria. The practical takeaway from the science is eat a variety, because different fibres are fermented at different rates and in different parts of the colon.67
Best food sources of fibre
Whole foods are the foundation. Approximate fibre content per typical serve:
| Food | Serve | Fibre (approx.) |
|---|---|---|
| Chia seeds | 2 tbsp | ~10g |
| Lentils (cooked) | ½ cup | ~8g |
| Black beans (cooked) | ½ cup | ~7g |
| Raspberries | 1 cup | ~8g |
| Avocado | ½ | ~5g |
| Rolled oats (cooked) | 1 cup | ~4g |
| Apple (with skin) | 1 medium | ~4g |
| Broccoli (cooked) | 1 cup | ~5g |
| Wholemeal bread | 2 slices | ~4g |
| Almonds | 30g | ~3.5g |
Values are approximate and vary by product and preparation.
For days when whole-food fibre falls short, a prebiotic fibre supplement can help top up the gap — ideally one that uses a blend of fibres rather than a single source.
How to increase your fibre without the bloating
Adding fibre too fast is the most common reason people feel bloated or gassy — the gut bacteria simply haven’t adjusted yet.7 To stay comfortable:
- Start low, go slow. Increase over 1–2 weeks rather than all at once.
- Drink more water. Fibre works best when it’s well hydrated.
- Favour variety. Several gentle fibres are easier on the gut than a big dose of one harsh fibre.
- Consider low-FODMAP options if you have a sensitive gut.
- Be consistent. The microbiome adapts with regular intake over weeks.
If you have IBS, a diagnosed digestive condition, or you’re pregnant or on medication, check with your GP or dietitian before making big changes.
Where a fibre supplement fits
Food first, always — but modern, busy diets often fall short of 25–30g a day. A well-formulated prebiotic fibre blend is a simple way to close that gap. Belo’s 6-in-1 Prebiotic Fibre Blend combines six gentle fibres that ferment at different speeds across the gut, delivering 11g of dietary fibre per serve, formulated to be low FODMAP and unflavoured so it’s easy to stir or bake into everyday food. It’s designed for exactly the comfortable, gradual approach the science supports.
Frequently asked questions
What are the main benefits of fibre?
The best-evidenced benefits are improved digestion and regularity, feeding a healthy gut microbiome, supporting healthy cholesterol and blood-sugar levels, and — at a population level — a lower long-term risk of heart disease, type 2 diabetes and bowel cancer.12
How much fibre should I eat per day?
In Australia, the Adequate Intake is about 25g/day for women and 30g/day for men, though many people benefit from aiming a little higher. Most Australians currently fall short.34
What’s the difference between soluble and insoluble fibre?
Soluble fibre dissolves in water and forms a gel that slows digestion (good for cholesterol and blood sugar); insoluble fibre adds bulk and helps move waste through the gut (good for regularity). Most foods contain both.
Does fibre help with bloating, or cause it?
Both — it depends on how you add it. Too much, too fast (especially a single harsh fibre) commonly causes bloating, while a gradual increase in varied, gentle fibres usually improves comfort over time.7
Can I get enough fibre from supplements alone?
Supplements are best used to top up a food-first diet, not replace it. Whole foods provide fibre alongside other nutrients, but a prebiotic fibre blend can help close the gap on busy days.
Is prebiotic fibre the same as a probiotic?
No. Prebiotic fibre is the food that feeds beneficial bacteria; probiotics are live bacteria. They work together.6
References
- Reynolds A, et al. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet. 2019;393(10170):434–445. doi:10.1016/S0140-6736(18)31809-9
- Veronese N, et al. Dietary fiber and health outcomes: an umbrella review of systematic reviews and meta-analyses. Am J Clin Nutr. 2018;107(3):436–444. doi:10.1093/ajcn/nqx082
- National Health and Medical Research Council (NHMRC). Nutrient Reference Values for Australia and New Zealand — Dietary Fibre. eatforhealth.gov.au
- Fayet-Moore F, et al. Dietary fibre intake in Australia. Nutrients. 2018;10(5):599. doi:10.3390/nu10050599
- Slavin J. Fiber and prebiotics: mechanisms and health benefits. Nutrients. 2013;5(4):1417–1435. doi:10.3390/nu5041417
- Gibson GR, et al. ISAPP consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol. 2017;14(8):491–502. doi:10.1038/nrgastro.2017.75
- Gill SK, Rossi M, Bajka B, Whelan K. Dietary fibre in gastrointestinal health and disease. Nat Rev Gastroenterol Hepatol. 2021;18(2):101–116. doi:10.1038/s41575-020-00375-4
- Koh A, et al. From dietary fiber to host physiology: short-chain fatty acids as key bacterial metabolites. Cell. 2016;165(6):1332–1345. doi:10.1016/j.cell.2016.05.041
- McRorie JW, McKeown NM. Understanding the physics of functional fibers in the gastrointestinal tract. J Acad Nutr Diet. 2017;117(2):251–264. doi:10.1016/j.jand.2016.09.021