The liver stores sugar as glycogen and is also capable of producing sugar from fatty acids and amino acids if food does not supply adequate sugar. Slow absorption of sugars is better tolerated than the rapid absorption of larger amount. Complex carbohydrates in vegetables are ideal sustained-release sources of sugar. Fiber There are several different types of carbohydrate polymers in fruit and vegetables that we are unable to digest. This material passes through the GIT as bulk fiber , undergoing modification and digestion by colon microorganisms.
Several fibers have benevolent roles.
The benefit seems to be the absorption or neutralization of the irritation or toxicity of other foods. Increased dietary fiber over a lifetime is associated with decreased incidence of bowel cancer and cardiovascular disease. The colon's dense population of microorganisms are very important to us in health and disease. Many vegetables contain indigestible carbohydrate, welcomed by the colon flora. The gas associated with beans is produced by the fermentation of these carbohydrates.