As part of the colon, fiber, also called roughage, is a source of plant-based carbohydrates that cannot be digested in the small intestine. No matter how inefficient it is as a body fuel, however, its importance cannot be denied. Fiber can be categorized into two types: soluble and insoluble fiber. Solvatile fiber dissolves in water easily as its name implies. Fibre that dissolves in water is known as soluble fiber, while fiber that does not dissolve is known as insoluble fiber. Since gut bacteria can metabolize soluble fiber, it is called fermentable fiber. Some scientifically proven health benefits of fiber are discussed below.