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11 November, 2026

Protein gets most of the attention in fitness circles, and for good reason. But there’s another nutrient that most people fall well short on, and it may matter just as much for long-term health: fibre.

Fibre feeds the trillions of bacteria living in your gut, keeps you fuller for longer, helps steady your blood sugar and protects your heart. Some of the most important research on fibre was led from right here in New Zealand, at the University of Otago. In this article we’ll look at what fibre does, how much you need, and easy ways to eat more of it.

What is fibre?

Fibre is the part of plant foods that your body can’t fully digest. Instead of being absorbed in your small intestine, it travels to your large intestine, where it either adds bulk or is fermented by your gut bacteria.

There are two main types, and most plant foods contain a mix of both:

  • Soluble fibre dissolves in water to form a gel. It slows digestion, helps lower cholesterol and steadies blood sugar. Good sources include oats, barley, legumes, apples and citrus fruit.
  • Insoluble fibre adds bulk and helps food move through your gut, keeping you regular. Good sources include wholegrains, nuts, seeds and the skins of vegetables and fruit.

Some fibres are also called prebiotics, because they are especially good food for beneficial gut bacteria. Onions, garlic, leeks, asparagus, slightly green bananas and legumes are rich in these.

Why fibre matters

1. It protects your heart and helps you live longer

In 2019, a major series of reviews led by the University of Otago and published in The Lancet pulled together nearly 250 studies and clinical trials. People who ate the most fibre had a 15 to 30% lower risk of death from any cause, heart disease, stroke, type 2 diabetes and bowel cancer compared with those who ate the least.

The biggest benefits were seen at around 25 to 29 grams of fibre a day, and the research suggested that eating even more may offer further protection.

2. It feeds your gut microbiome

When your gut bacteria ferment fibre, they produce compounds called short-chain fatty acids. These help keep the lining of your gut healthy and appear to play a role in managing inflammation and metabolism. Research on the gut microbiome is moving quickly, and many of the details are still being worked out, but it’s clear that a diet rich in a variety of plant foods supports a healthier gut community.

3. It helps with appetite and weight management

Fibre-rich foods are filling and take longer to eat and digest. That can help you feel satisfied on fewer kilojoules, which is useful if you’re trying to lose weight or avoid overeating.

4. It steadies blood sugar

Soluble fibre slows the absorption of sugar from a meal, which means smaller blood sugar spikes. Pair it with a walk after eating (see our recent post on walking after meals) and you’ve got a powerful combination.

5. It keeps things moving

The most familiar benefit: fibre, along with enough water, helps prevent constipation and keeps your digestion regular.

A note on fermented foods

Fermented foods, such as yoghurt, kefir, sauerkraut, kimchi and kombucha, are often mentioned alongside fibre for gut health. A 2021 study from Stanford University found that a diet high in fermented foods increased the variety of bacteria in the gut and lowered markers of inflammation over 10 weeks. Interestingly, a high-fibre diet didn’t change gut bacteria variety in that short time, though it had other effects.

It’s one study, and both approaches have their place. The take-home message: eat plenty of fibre and include some fermented foods for the best of both worlds.

How much fibre do you need?

The recommended intake in New Zealand and Australia is about:

  • 25 grams a day for women
  • 30 grams a day for men

Most of us fall short of these targets. A simple way to picture 30 grams:

  • A bowl of rolled oats with berries and a spoonful of chia seeds (about 10 grams)
  • A wholegrain sandwich with salad (about 6 grams)
  • An apple and a handful of almonds (about 6 grams)
  • Dinner with half a plate of vegetables and some lentils, beans or chickpeas (about 10 grams)

Fibre content varies by brand and portion size, so check food labels, which list fibre per serving.

Practical tips to eat more fibre

  1. Swap to wholegrains. Choose wholegrain bread, brown rice, wholemeal pasta and rolled oats over refined white versions.
  2. Add legumes. Toss a tin of chickpeas, lentils or kidney beans into soups, stews, curries, salads or mince dishes.
  3. Eat the skin. Keep the skins on potatoes, kūmara, apples and pears where you can.
  4. Make half your plate vegetables. Fresh, frozen or tinned all count. Frozen veges are cheap, convenient and just as nutritious.
  5. Snack on nuts, seeds and fruit. A handful of nuts or a piece of fruit beats a packet of chips.
  6. Aim for variety. Different plants feed different gut bacteria. Try to eat a wide range of vegetables, fruit, grains, nuts, seeds and legumes each week.
  7. Go slowly and drink water. Increase your fibre over a couple of weeks and drink plenty of water to avoid bloating and wind while your gut adjusts.

Who should be careful

  • If you have irritable bowel syndrome (IBS), inflammatory bowel disease or another gut condition, some high-fibre foods may trigger symptoms. A dietitian can help you find the right types and amounts for you.
  • If you notice a lasting change in your bowel habits, blood in your stools or unexplained weight loss, see your GP.

Conclusion

Fibre is one of the simplest and most powerful upgrades you can make to your diet. It feeds your gut, protects your heart, helps manage your weight and blood sugar, and is linked to a longer life. Most of us need more of it, and getting there is as easy as a few smart swaps.

Want help putting together an eating plan that supports your training and your long-term health? Our trainers offer nutrition guidance alongside training, in person and online. Book a free consultation with Advantage Fitness, call us on 022 0246 145, or email enquire@advantagefitness.co.nz.

This article is general information only and is not medical advice. If you have a gut condition, talk to your GP or a registered dietitian before making big changes to your diet.

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