"Roughage" such as lettuce, fruits, and other fibers, are important to loosen things up in your digestive system so that you do not get constipated. That is why when you eat some fruits or vegetables you can get gas, or have to go to the bathroom more often. This is why eating fruits and vegetables will help you lose weight besides giving you more energy with out feeling weight down.
Dietary fiber or roughage refers to the indigestible fibrous material e.g. cellulous, present in the diet. It is important because it provides volume to the intestinal contents and helps in peristalsis.
Peristalsis is a series of wavelike, muscular movements of the walls of the digestive tract. These movements enable food to be mixed with the digestive juices. In addition to this, they allow the food to move along in the digestive tract. In the peristaltic movements are not proper, the food in the large intestines in not able to move at the required rate. This results in excessive water absorption. As a result, the face become too dry and hard and their movement through the anus becomes difficult. This condition is called constipation. It can be prevented by taking enough fiber and drinking sufficient water. Regular exercise also helps to promote the peristaltic movements.
There are soluble and insoluble types of dietary fiber. Soluble fibers are found in legumes, certain vegetable like broccoli, carrots, potatoes and onions. Fruits and fruit juices also contain soluble fibers. Insoluble fibers are present in whole wheat foods, bran and cereals and green vegetables. Skins of certain fruits, such as tomatoes also contain dietary fiber.
