Carbohydrate

From Atkinspedia

Carbohydrates are chemical compounds that contain oxygen, hydrogen, and carbon atoms. They may also contain other elements such as sulfur or nitrogen, but these are usually minor components.

As one of the nutrients that supply calories to the body, Carbohydrates require less water to digest than proteins or fats and are the most common source of energy. Proteins and fat are vital building components for body tissue and cells, and thus it could be considered advisable not to deplete such resources by necessitating their use in energy production. Carbohydrates, like proteins, contain 4 kilocalories per gram while fats contain 9 kilocalories and alcohol contains 7 kilocalories per gram.

Classification

Dietitians and nutritionists commonly classify carbohydrates as simple (monosaccharides and disaccharides) or complex (oligosaccharides and polysaccharides), depending on their chemical structure. The term complex carbohydrate was first used in the Senate Select Committee publication Dietary Goals for the United States (1977), where it denoted "fruit, vegetables and whole-grains". Dietary guidelines generally recommend that complex carbohydrates and nutrient-rich simple carbohydrates such as fruit and dairy products should make up the bulk of carbohydrate consumption. The USDA's Dietary Guidelines for Americans 2005 dispenses with the simple/complex distinction, instead recommending fiber-rich foods and whole grains.

The glycemic index and glycemic load systems are popular alternative classification methods which rank carbohydrates based on their effect on blood glucose levels.

Sources of carbohydrates include Grains, fruits, vegetables, nuts, legumes and other plant foods. When completely broken down in the body, a gram of carbohydrate yields about four calories. When following the Food Guide Pyramid, Americans consume at least 300 grams of carbohydrate daily. The Atkins Nutritional Approach, on the other hand, advises considerably lower carbohydrate intake and the more active an individual, the higher the tolerance. Atkins also concentrates on vegetables and other nutrient-dense carbohydrates rather than refined, heavily processed carbohydrates such as white flour and Sugar.