In the early 1900s, Americans were consuming about 65 to 75 percent of their calories from low sugar, complex carbohydrate food sources. This earlier eating pattern is thought to be better for optimal health. Sugars now account for 12 percent of an average American's daily diet. This is much more than the recommended intake of less than 5 percent from simple sugars and the remainder from complex carbohydrates. In order to get enough carbohydrates, an average American consuming 2,000 calories each day needs to eat between 290 and 300 grams of carbohydrates daily, which is about 60 percent of calories from carbohydrates.
Carbohydrates have several functions in the body.
First, they are a major source of energy. Second, they have a protein-sparing effect that protects muscle tissue from being broken down. And third, carbohydrates are the major fuel source for the brain. Complex carbohydrates are also high in dietary fiber, which is important for maintaining normal functioning of the digestive tract. The USDA Food Guide Pyramid recommends 6 to 11 servings of complex carbohydrates everyday.