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Carbohydrates

Contents of this page:

Illustrations

Complex carbohydrates
Complex carbohydrates
Simple carbohydrates
Simple carbohydrates
Starchy foods
Starchy foods

Alternative Names    Return to top

Starches; 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:

Simple carbohydrates that contain vitamins and minerals occur naturally in: Simple carbohydrates are also found in processed and refined sugars such as:

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:

Here are recommended serving sizes for foods high in carbohydrates:

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).

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The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2009, A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.