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Alternative Names Return to topStarches; Simple sugars; Sugars; Complex carbohydrates; Diet - carbohydrates; Simple carbohydrates
Definition Return to top
Carbohydrates are one of the main dietary components. This category of foods includes sugars, starches, and fiber.
Function Return to top
The primary function of carbohydrates is to provide energy for the body, especially the brain and the nervous system. An enzyme called amylase helps break down carbohydrates into glucose (blood sugar), which is used for energy by the body.
Food Sources Return to top
Carbohydrates are classified as simple or complex. The classification depends on the chemical structure of the food, and how quickly the sugar is digested and absorbed. Simple carbohydrates have one (single) or two (double) sugars. Complex carbohydrates have three or more sugars.
Examples of single sugars from foods include:
Double sugars include:
Honey is also a double sugar. But unlike table sugar, it contains a small amount of vitamins and minerals. (NOTE: Honey should not be given to children younger than 1 year old.)
Complex carbohydrates, often referred to as "starchy" foods, include:
Refined sugars provide calories, but lack vitamins, minerals, and fiber. Such simple sugars are often called "empty calories" and can lead to weight gain.
Also, many refined foods, such as white flour, sugar, and polished rice, lack B vitamins and other important nutrients unless they are marked "enriched." It is healthiest to get carbohydrates, vitamins, and other nutrients in as natural a form as possible -- for example, from fruit instead of table sugar.
Side Effects Return to top
Recommendations Return to top
Most people should get between 40% and 60% of total calories from carbohydrates, preferably from complex carbohydrates (starches) and natural sugars. Complex carbohydrates provide calories, vitamins, minerals, and fiber.
Foods that are high in processed, refined simple sugars provide calories, but very little nutrition. It is wise to limit these sugars.
To increase complex carbohydrates and healthy nutrients:
For information about how many servings are recommended, see the food guide pyramid.
Here is a sample 2,000 calorie menu, of which 50% - 60% of the total calories are from carbohydrates.
References Return to top
Farrell JJ. Digestion and Absorption of Nutrients and Vitamins. In: Feldman M, Friedman LS, Sleisenger MH, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 8th ed. Philadelphia, Pa: WB Saunders; 2006:chap 97.
Dietary Guidelines for Americans 2005. Rockville, MD: US Dept. of Health and Human Services and US Dept. of Agriculture; 2005.Update Date: 12/12/2008 Updated by: A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz. Previously reviewed by Linda Vorvick, MD, Family Practitioner, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine (8/22/2008).