In the body, the function of carbohydrates is to provide fuel or energy. The body needs carbohydrates to ensure that many organs of the body, such as the central nervous system, the heart muscle and the kidneys can function properly; they also aid in the performance of physical activity.
The body acquires carbohydrates through foods, such as fruits, vegetables, grains, milk, fiber and cereals. When a person eats carbohydrates, the digestive system converts them to glucose. The body can either use the glucose right away for energy or store it in the liver and muscles for later use. Excess glucose that the liver cannot store gets turned into fat. Every cell and tissue in the body requires glucose for energy, according to the McKinley Health Center.
Simple and complex carbohydrates are two types of carbohydrates used by the body. Complex carbohydrates include starch and dietary fiber. While foods like potatoes contain starch, fruits, oatmeal, grains and vegetables contain dietary fiber. Simple carbohydrates are substances like brown sugar, corn syrup and sugars added to processed food.
A person needs about 14 grams of dietary fiber per every 1000 calories that he consumes, according to the Center for Disease Control and Prevention. A low-fiber diet can lead to health problems like constipation and hemorrhoids, and it may increase the risk of colon cancer, according to the McKinley Health Center. Conversely, high-fiber diets may lower the risk of heart disease and being overweight.