How much fibre do you need each day?

Advanced Accredited Practising Dietitian, Lauren Atkins, wants you to aim higher with fibre.

Lauren advises that there’s an adequate intake of fibre each day, which is the minimum amount you need to keep your digestive system healthy and limit constipation.

“This is roughly 25 grams per day for women and 30 grams per day for men,” says Lauren.

“However, if we want to move beyond ‘just getting by’ and look at preventing long-term illness, we look at the suggested dietary target.

“This is a higher goal – 28 grams for women and 38 grams for men – specifically designed to help reduce the risk of chronic diseases like heart disease, type 2 diabetes, and certain cancers (especially bowel cancer).”¹

Fibre is a carbohydrate that can’t be digested in the small intestine. Instead, fibre passes into the large intestine or colon where gut microbiota breaks it down.² This process fuels the microbiota and sets off a chain reaction that helps the gut and other systems in the body.³ But it doesn’t stop there, because the digestive system is lined with muscles that massage food along the digestive tract, and it starts from the moment you eat until waste passes out of the bowel. Dietary fibre plays a key role in this process: not only does it add bulk to your poo, making it easier to pass, but it also helps stimulate these muscle contractions, and in turn, keeps your digestive system healthy and well-functioning.⁴

Health benefits of fibre

There are many health benefits to fibre that Lauren describes as impressive.

Gut health and healthy bowel movements

“Beyond the obvious benefit of regular bowel movements, fibre is a prebiotic. This means it acts as a food source for the ‘good’ bacteria in your gut. When these bacteria ferment fibre, they produce short-chain fatty acids that help reduce inflammation and support your immune system,” says Lauren.

Feel fuller for longer

“Fibre also helps you feel fuller for longer,” says Lauren.

How? Soluble fibre forms a gel that slows down the pace of food passing through the digestive system. This process extends the time you feel full.

Reduced risk of certain cancers

“There is even strong evidence that a high-fibre diet reduces the risk of certain cancers, particularly bowel cancer. It’s one of the simplest, most effective tools we have for long-term disease prevention,”⁵ says Lauren.

Reduced risk of diabetes and heart disease⁶

An increase in daily fibre intake has shown to have a positive effect on the health complications associated with diabetes because it helps to control blood glucose and lowers low-density lipoprotein cholesterol.⁷ Fibre is also shown to reduce the risk of heart disease because of the many health benefits of a fibre-rich diet.⁸

How to increase the amount of fibre in your diet

“The golden rule here is: low and slow,” says Lauren.

“Switch white bread for a seedy, wholegrain loaf this week. Next week, try adding half a tin of rinsed lentils into your spaghetti bolognese, some four-bean mix to your Mexican, berries to your brekky, an extra veggie to your lunch, or snack on a carrot or cucumber with some nuts.

“It’s also important to increase your water intake as you increase fibre. Since fibre (especially the soluble kind) soaks up water, you need that extra hydration to keep things lubricated and moving smoothly. Without water, extra fibre can actually lead to constipation.”

What’s the difference between soluble fibre and insoluble fibre?

Lauren describes the difference with the ‘sponge and broom’ analogy.

“Soluble fibre is like a sponge. It dissolves in water to form a gel-like substance in your gut. This helps slow down digestion, which is great for keeping your blood sugar stable and soaking up cholesterol to help your heart. It’s also really useful if you're prone to loose stools as it soaks up liquid to firm up stools. You’ll find this in foods like oats, beans, lentils, and the flesh of fruits and vegetables,” says Lauren.

“Insoluble fibre is like a broom. It doesn't dissolve in water and remains relatively intact as it moves through your system. Its main job is to add bulk to your stool and sweep everything along, preventing that sluggish, backed-up feeling, and keeping the lining of your gut healthy. This is found in the skins, strings and seeds of fruit, vegetables and legumes, as well as whole grains and nuts.”

Keep your ‘sponges’ and ‘brooms’ in good rotation to maintain the balance of different types of fibre in your digestive system.

But what does that look like on a plate?

“…roughly [it’s] the equivalent of eating two slices of high-fibre wholegrain bread, two pieces of fruit, five serves of vegetables, and a serving of legumes or a handful of nuts,” says Lauren.

Check the label if you’re unsure about the amount of fibre in food. Lauren notes that there a lot of foods or snacks that promote themselves as ‘high fibre’ but there is one line on the food ingredients panel to double check.

“When you’re looking at food labels, check the ‘dietary fibre’ line,” says Lauren.

“A ‘high-fibre’ food in Australia must contain at least 3 grams of fibre per serve, while ‘very high fibre’ means at least 6 grams per serve.

“Aim for bread and crackers that have at least 5 grams of fibre per 100 grams.”

READ MORE: Dietitian, nutritionist or naturopath: what's the difference?

What are fibre supplements? Should I take one?

There are lots of fibre supplements available that can support you daily fibre intake. Fibre supplements can be bought from the chemist and often come as a powder that can be mixed with liquid.

“As a dietitian, I’m a ‘food first’ advocate. Whole foods provide a complex matrix of vitamins, minerals, antioxidants and phytonutrients that a supplement simply can't replicate,” says Lauren.

“If you find it impossible to meet your needs through food alone, or if you have specific digestive goals, a supplement can help, but it’s always best to have a chat with an Accredited Practising Dietitian first to make sure you’re choosing the right type for your specific needs.”

Fibremaxxing trend – can you eat too much fibre?

A recent social media trend has been ‘fibremaxxing’, which is where people try to hit huge targets for daily fibre intake with the help of supplements and powders.

Lauren appreciates the enthusiasm about gut health but says you don’t need to overdo it.

“...it’s important to remember that our gut is an ecosystem, not a competitive sport,” says Lauren.

“Overdoing it too quickly, or relying solely on isolated fibre supplements rather than whole foods, can lead to significant discomfort and can actually hinder the absorption of some essential minerals like calcium and zinc.”

“When this comes up, I steer people away from the "maxing" mindset and back towards the "optimising" mindset. It’s not just about the total grams; it’s about the variety of plant sources and the consistency of your intake.”

READ MORE: 4 easy ways to eat more vegetables

The relationship between fibre and carbohydrates

As a dietitian, Lauren often hears from people who have lots of questions about fibre and carbohydrates (carbs), but the key is to understand how they work together in your body.

“I like to think of fibre as the ‘security guard’ for carbohydrates,” says Lauren.

“When you eat a refined carbs (like a piece of white bread or a sugary biscuit), the sugar is absorbed into your bloodstream quickly, causing a spike in energy, followed by a crash.

“When that same carbohydrate comes wrapped in fibre (like in a bowl of oats, a sweet potato with the skin on, a serving of lentils, or even a spread of hummus on that same white bread), that ‘security guard’ slows down the digestion and absorption of those sugars. This gives you a slow, steady release of energy and keeps your blood sugar – and energy - levels much more stable.”

There’s one more piece of advice that Lauren has for any fibre changes in your diet.

“Your body is the best feedback loop you have,” says Lauren.

“Pay attention to how different fibre sources make you feel. There is no one size fits all approach, which is why partnering with a dietitian can be so helpful to find your specific sweet spot.”