Why dietary fibre is essential for gut health, blood sugar, cholesterol and metabolic health, plus how much fibre Australian adults need each day.
Why fibre matters: the overlooked nutrient most Australians need more of
Fibre was once regarded as little more than “roughage”. Something that helped keep digestion regular. Research now suggests its role is much broader. Dietary fibre supports gut health, helps regulate blood sugar and cholesterol, contributes to fullness and may help protect against several chronic diseases.
Despite this, most Australians are still not eating enough.
What is dietary fibre?
Dietary fibre resists digestion in the small intestine. Instead of being broken down and absorbed like many other carbohydrates, it continues into the large intestine, where different fibres each behave in different ways.
Some add bulk and support regular bowel movements. Some absorb water and form viscous gels. Others are fermented by gut bacteria, producing compounds such as short-chain fatty acids that help support the intestinal environment.
When we address “fibre” in our diets, it is critical to understand that it is not a single ingredient with a single function. Different fibre sources can have different physical properties and physiological effects.
Soluble fibre and insoluble fibre
The University of Wollongong identifies two broad categories of dietary fibre:
-
Soluble fibre disperses or dissolves in water. Some soluble fibres form a gel that slows the movement of food through the digestive tract. Depending on the specific fibre, this can support satiety and help moderate post-meal blood glucose or maintain healthy cholesterol levels. Soluble fibre is found in foods including oats, legumes, fruit and vegetables.
-
Insoluble fibre does not dissolve in water. It generally adds bulk to stool and helps material move through the digestive tract. Sources include whole grains, wheat bran and the skins of many fruits and vegetables.
Fibre, prebiotics and the gut microbiome
Certain fermentable fibres act as prebiotics: they are selectively used by beneficial microorganisms in the gut and provide a health benefit.
When gut bacteria ferment these fibres, they produce short-chain fatty acids. These compounds play important roles in the colon, including helping nourish cells in the intestinal lining and supporting the gut environment.
This connection between dietary fibre and the gut microbiome is one reason fibre is now being investigated for effects extending beyond bowel regularity including metabolic regulation, inflammation and potentially aspects of mood and cognitive health.
Fibre and metabolic health
The UOW researchers are particularly interested in the relationship between low fibre intake and metabolic syndrome.
Metabolic syndrome describes a cluster of risk factors that can include abdominal obesity, high blood pressure, insulin resistance and abnormal blood lipid levels. Together, these factors increase the risk of conditions such as type 2 diabetes, cardiovascular disease and stroke.
Fibre may support metabolic health in several complementary ways. Depending on the type and dose, it can:
-
support a diverse and functional gut microbiome;
-
contribute to the production of short-chain fatty acids;
-
slow carbohydrate absorption and moderate blood glucose responses;
-
help maintain healthy cholesterol levels;
-
increase fullness and support appetite regulation; and
-
support regular bowel function.
Fibre is not a treatment for metabolic syndrome, but consuming sufficient fibre as part of a balanced diet is associated with better long-term health outcomes.
How much fibre do you need each day?
Australian dietary recommendations generally set an adequate daily fibre intake of approximately:
Higher suggested dietary targets around 28 grams for women and 38 grams for men are associated with reducing the risk of chronic disease.
Yet data cited by the University of Wollongong indicates that fewer than 20 per cent of Australian adults consume the amount of fibre recommended for chronic-disease risk reduction.
Why are modern diets so low in fibre?
Traditional diets obtained fibre from a wide variety of whole plant foods. Modern Western diets tend to contain more refined grains, convenience foods, sugary cereals and other ultra-processed foods from which much of the natural fibre has been removed.
At the same time, fibre-rich staples such as legumes, whole grains, vegetables, fruit, nuts and seeds are often under-consumed.
The result is not simply less fibre, but often less fibre diversity. Eating different plant foods provides fibres with different structures and functions, giving the digestive system and gut microbiome a broader range of substrates.
How to increase your fibre intake
Useful dietary sources include:
-
beans, chickpeas and lentils;
-
oats, barley and whole grains;
-
vegetables and leafy greens;
-
whole fruit, including edible skins where appropriate;
-
nuts and seeds; and
-
resistant-starch-containing foods.
Increase fibre gradually, particularly if your current intake is low, and drink adequate water. A rapid increase can cause temporary bloating or digestive discomfort while the gut adjusts.
The central message from the UOW research is simple: fibre deserves to be treated as more than a digestive aid. Eating enough and obtaining it from varied sources can support the gut, the microbiome and wider metabolic health throughout life.
Want to learn more?
See the original research: https://www.uow.edu.au/the-stand/2025/why-fibre-matters.php
Article by: India Glyde
Why Fibre Matters: Gut Health, Blood Sugar and Metabolic Health
Why dietary fibre is essential for gut health, blood sugar, cholesterol and metabolic health, plus how much fibre Australian adults need each day.
Why fibre matters: the overlooked nutrient most Australians need more of
Fibre was once regarded as little more than “roughage”. Something that helped keep digestion regular. Research now suggests its role is much broader. Dietary fibre supports gut health, helps regulate blood sugar and cholesterol, contributes to fullness and may help protect against several chronic diseases.
Despite this, most Australians are still not eating enough.
What is dietary fibre?
Dietary fibre resists digestion in the small intestine. Instead of being broken down and absorbed like many other carbohydrates, it continues into the large intestine, where different fibres each behave in different ways.
Some add bulk and support regular bowel movements. Some absorb water and form viscous gels. Others are fermented by gut bacteria, producing compounds such as short-chain fatty acids that help support the intestinal environment.
When we address “fibre” in our diets, it is critical to understand that it is not a single ingredient with a single function. Different fibre sources can have different physical properties and physiological effects.
Soluble fibre and insoluble fibre
The University of Wollongong identifies two broad categories of dietary fibre:
Fibre, prebiotics and the gut microbiome
Certain fermentable fibres act as prebiotics: they are selectively used by beneficial microorganisms in the gut and provide a health benefit.
When gut bacteria ferment these fibres, they produce short-chain fatty acids. These compounds play important roles in the colon, including helping nourish cells in the intestinal lining and supporting the gut environment.
This connection between dietary fibre and the gut microbiome is one reason fibre is now being investigated for effects extending beyond bowel regularity including metabolic regulation, inflammation and potentially aspects of mood and cognitive health.
Fibre and metabolic health
The UOW researchers are particularly interested in the relationship between low fibre intake and metabolic syndrome.
Metabolic syndrome describes a cluster of risk factors that can include abdominal obesity, high blood pressure, insulin resistance and abnormal blood lipid levels. Together, these factors increase the risk of conditions such as type 2 diabetes, cardiovascular disease and stroke.
Fibre may support metabolic health in several complementary ways. Depending on the type and dose, it can:
support a diverse and functional gut microbiome;
contribute to the production of short-chain fatty acids;
slow carbohydrate absorption and moderate blood glucose responses;
help maintain healthy cholesterol levels;
increase fullness and support appetite regulation; and
support regular bowel function.
Fibre is not a treatment for metabolic syndrome, but consuming sufficient fibre as part of a balanced diet is associated with better long-term health outcomes.
How much fibre do you need each day?
Australian dietary recommendations generally set an adequate daily fibre intake of approximately:
25 grams per day for adult women
30 grams per day for adult men
Higher suggested dietary targets around 28 grams for women and 38 grams for men are associated with reducing the risk of chronic disease.
Yet data cited by the University of Wollongong indicates that fewer than 20 per cent of Australian adults consume the amount of fibre recommended for chronic-disease risk reduction.
Why are modern diets so low in fibre?
Traditional diets obtained fibre from a wide variety of whole plant foods. Modern Western diets tend to contain more refined grains, convenience foods, sugary cereals and other ultra-processed foods from which much of the natural fibre has been removed.
At the same time, fibre-rich staples such as legumes, whole grains, vegetables, fruit, nuts and seeds are often under-consumed.
The result is not simply less fibre, but often less fibre diversity. Eating different plant foods provides fibres with different structures and functions, giving the digestive system and gut microbiome a broader range of substrates.
How to increase your fibre intake
Useful dietary sources include:
beans, chickpeas and lentils;
oats, barley and whole grains;
vegetables and leafy greens;
whole fruit, including edible skins where appropriate;
nuts and seeds; and
resistant-starch-containing foods.
Increase fibre gradually, particularly if your current intake is low, and drink adequate water. A rapid increase can cause temporary bloating or digestive discomfort while the gut adjusts.
The central message from the UOW research is simple: fibre deserves to be treated as more than a digestive aid. Eating enough and obtaining it from varied sources can support the gut, the microbiome and wider metabolic health throughout life.
Want to learn more?
See the original research: https://www.uow.edu.au/the-stand/2025/why-fibre-matters.php
Article by: India Glyde