The most significant food sources of fibre are unprocessed wheat bran, whole cereals such as wheat, rice, barley, rye, millets ; legumes such as potato, carrots, beet , turnip and sweet potato ; fruits like mango and guava and leafy vegetables such as cabbage, lettuce and celery. The percentage of fibre content per 100 gms. of some foods are : bran 10.5-13.5, whole grain cereals 1.0-2.0, nuts 2.0-5.0, legumes 1.5-1.7, vegetables 0.5-1.5, fresh fruits 0.5-1.5, and dried fruits 1.0-3.0. The foods which are completely devoid of fibre are meat, fish , eggs, milk, cheese, fats and sugars.

Bran, the outer coverings of grains, is one of the richest sources of dietary fibre. And it contains several types of fibre including cellulose, hermicellulose and pectin. Wheat and corn bran are highly beneficial in relieving constipation. Experiments show that oat bran can reduce cholesterol levels substantially. Corn bran is considered more versatile. It relieves constipation and also lowers LDL cholesterol, which is one of the more harmful kinds. Besides being rich in fibre, bran has a real food value being rich in time, iron and vitamins and containing a considerable amount of protein.

Dr.Dennis P. Burkitt, a noted British physician remarks, " Grain roughages, such as rich bran and wheat bran, are an essential part of a healthy diet, and a preventive against diseases like piles, constipation, bowel cancer, varicose veins and even coronary thrombosis. " Dr. Burkitt worked for many years in Africa and found after a series of observations that rural Africans who eat bulk of fibrous foods rarely suffer from any of these diseases.

Legumes have high fibre content. Much of this fibre is water- soluble, which makes legumes likely agents for lowering cholesterol. Soyabeans, besides this, can also help control glucose levels.
The types of fibre contained in vegetables and fruits contribute greatly towards good health. The vegetables with the biggest fibre ratings include sweet corn, carrots, potatoes, parsnips and peas. And among the high ranking fruits are raspberries, pears, strawberries and guavas.

Dietary fibre differs from other nutrients in that it is not digested in the small intestine. Instead, some of it undergoes changes in the large intestine which can have a variety of effects on the body. Dietary fibre is a mixture of different substances. Some of these can 'dissolve' in water (soluble fibre) and the description of dietary fibre as roughage and fibrous can be misleading.

Dietary fibre from different sources differ in the relative amount of each of their components. For example, wheat bran contains high amounts oi insoluble fibre while oat bran has high amounts of soluble fibre. Because each component has different chemical and biological properties, the biological result of consuming dietary fibre from different foods differs.

Examine snacks as well as main meals to find out where fats (spreads and oils, and cooking fat in cakes and pastries) and refined carbohydrate (sugar in confectionery and biscuits) can be replaced with foods containing dietary fibre (see the following sources of dietary fibre).

Dietary fibre is mostly carbohydrate (and a little 'lignin') which is not digested in the small intestine but may be fermented in the large intestine. It is 'non-starch polysaccharide'. However, some starch resists digestion too, and behaves like dietary fibre. Unripe or partially ripe bananas are a good source of resistant starch and dietary fibre. Dietary fibre has important functions in the large bowel and some breaks down there under the consuming (kilojoules) at about 13 kilojoules per gram of dietary fibre (3 kilocalories).

It is best to obtain dietary fibre from a variety of foods because its chemistry is different in different foods and its effects on food structure differ from food to food.