Dietary fibre consists of indigestible components of plant foods that are not broken down in the small intestine but take on important functions in the large intestine. A rough distinction is made between soluble fibre, for example from oats or pulses, and insoluble fibre, for example from wholegrain products and vegetable skins.
Fibre binds water, increases stool volume and thereby supports regular digestion. Part of the soluble fibre is also fermented by bacteria in the large intestine, which plays a role for the gut flora too.
Relevance for nutrition and sport
For physically active people, fibre is relevant because of its contribution to satiety and digestive health, among other things. Because fibre slows gastric emptying, some people deliberately eat less fibre before intense training to avoid digestive discomfort during exertion.
Spread over the day, an adequate fibre intake from wholegrain products, pulses, vegetables and fruit is generally considered favourable for digestion and long-term satiety. A very sudden increase in the amount of fibre can temporarily cause bloating, so a gradual increase makes sense. The guide carbohydrates explains more about carbohydrate-containing foods, including high-fibre sources. Enough fluid also supports the effect of fibre in the gut, as otherwise it can only partly develop its swelling properties.
