The so-called vegetable fibers are indigestible substances for humans but that have healthy effects for the body, especially, to make faster digestion avoiding the constipation and the negative implications that this disorder causes.
Vegetable fiber is cellulose, the same component of the paper, a natural polysaccharide made up of a large number of beta glucose units. Beta-glucose is an isomer of alpha-glucose, our energy fuel par excellence, and the only difference between the two molecules is the position of the hydroxyl functional group on carbon 1 of the closed chain.
Humans cannot hydrolyze cellulose, we do not have a metabolic pathway or an enzyme that allows us, in some part of the digestive system, to break the bond called 1,4 glucosidic between the beta glucose units, therefore, cellulose is not a nutrient for us since it does not we digest it. Only a very small part of the vegetable fiber can lead to the release of fatty acids in the intestine due to its fermentation.
On the other hand, ruminants have a bacterium in one of their digestive compartments that allows them to degrade cellulose and convert it into a source of energy. That is why they can generate fat from the intake of large volumes of cellulose that they obtain from the grass they eat.
Cellulose is a starch-like carbohydrate (We can digest this one) only that starch is made up of alpha glucose units. Cellulose has a structural function in vegetables: to give shape and support to their leaves and stems. Hemicellulose and lignin are other minor components of vegetable fiber.
The advantage in digestion of the consumption of vegetable fibers (especially raw) is that it absorbs water, almost the same weight in water, helping to delay the absorption of nutrients, which is better distributed and contributes to giving a feeling of satiety. In the function of dragging waste matter from the intestine which causes a more complete digestion avoiding the accumulation of feces in the intestine.
In weight loss diets, fiber intake is essential. There is no diet without fiber because it collaborates from various points of view. The fibers are not fattening, give a feeling of fullness and cleanse the digestive system.