Fibre
Definition
What 'Fibre' means
Found exclusively in plant foods, it passes relatively intact through the digestive tract to fuel beneficial gut bacteria. Through solubility and fermentation, it helps manage cholesterol levels, slows glucose absorption, and adds physical bulk to stool.
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In depth
The longer answer
Dietary fibre refers to the diverse group of plant-derived carbohydrates that the human body cannot fully digest or absorb. Found exclusively in plant foods like legumes, whole grains, vegetables, and fruits, it passes relatively intact through the stomach and small intestine. While it provides negligible calories, it serves as a critical structural component of plant cell walls and acts as a primary fuel source for the beneficial bacteria residing in the human gut microbiome.
In the digestive tract, fibre functions through two primary mechanisms: solubility and fermentation. Soluble fibre dissolves in water to form a viscous gel, which slows the absorption of glucose and binds to bile acids to help manage cholesterol levels. Insoluble fibre adds physical bulk to the stool and stimulates peristalsis, accelerating the passage of food through the colon. Meanwhile, gut microbes ferment certain fibres into short-chain fatty acids, which nourish the colon lining and regulate systemic inflammation.
For the modern consumer, increasing fibre intake is one of the most effective ways to improve metabolic health and satiety. However, the 'fibre gap' remains a significant public health issue, as most people consuming highly processed diets fall far short of recommended daily targets. While supplements exist, they rarely replicate the complex matrix of phytonutrients found in whole plants. Rapidly increasing intake can cause temporary bloating, so it is best to transition gradually while maintaining consistent hydration.
At a glance
Quick facts
- Daily Target
- 25 to 38 grams for most adults
- Primary Sources
- Legumes, whole grains, nuts, and seeds
- Synonyms
- Roughage, bulk, non-starch polysaccharides
- Caloric Value
- Approximately 2 calories per gram
| Detail | What to know |
|---|---|
| Daily Target | 25 to 38 grams for most adults |
| Primary Sources | Legumes, whole grains, nuts, and seeds |
| Synonyms | Roughage, bulk, non-starch polysaccharides |
| Caloric Value | Approximately 2 calories per gram |
In practice
What this means for you
- Choose whole fruits over fruit juices to retain the essential structural fibre lost during the juicing process.
- Swap refined white grains for intact versions like farro, quinoa, or brown rice to increase meal density.
- Add a half-cup of lentils or beans to soups and salads to easily reach daily intake goals.
- Check nutrition labels for at least three grams of fibre per serving when buying packaged breads.
FAQ