Fiber -- or non-digestible nutrients found in plants -- helps you to digest food. Soluble and insoluble fiber are the two classes of fiber that facilitate digestion. Water-soluble fiber such as pectin, gum and mucilage slacken digestion processes and mop up excess fats from your body. Insoluble fiber such as lignin and cellulose helps with food movement and binds stools as they travel through your digestive system. Fiber is plentiful in whole grains, legumes, fruits and vegetables.
Food Absorption
Soluble fiber, such as pectin and gum, drags the flow of food in your small intestines. This slows the digestion and absorption of carbs and effectively moderates your blood sugar levels. Whereas rapid conversion of carbs to glucose enhances your body energy, it could easily trigger weight gain if excess glycogen -- or converted glucose -- is turned into fat. Controlled sugar intake shields your body from health complications such as Type 2 diabetes and heart disease that come with excess weight.
Laxation
Fiber injects water into your stool, binds it and hastens its passage through the large intestines -- or colon. This induces laxation and prevents the occurrence of fragmented and dry stool that causes constipation. Similarly, when your stool is loose, soluble fiber sets in to slow its movement in your colon. The colon absorbs the excess water from the loose stool and consolidates it into bulk chunks. The smooth movement of food from the stomach to the small intestines and the colon -- aided by dietary fiber -- is a very important function of the digestion process.
Excess Fat
When soluble fiber dissolves in water, it forms a gel that traps and flushes out the excess fat in your meals. This prevents the excess fat from penetrating your digestive system, ridding your body of harmful elements such as excess low-density lipoprotein -- or bad cholesterol. Bad cholesterol causes heart disease when it accumulates along the walls of your arteries.
Fermentation
Fiber facilitates fermentation of food substances that form in your colon. Fermentation involves the digestion of nutrient substances such as resistant starch, alcohol sugars and lactose that could not be digested in your small intestines. When the non-digested nutrient substances reach your colon, they are subjected to fermentation process that completely degrades and converts them into energy. The fermentation processes in the colon also aids the digestion of portions of some soluble fibers such as pectin to produce energy.