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What Is a Carbohydrate?

All About Complex Carbohydrates


Simple carbohydrates (simple sugars) are molecules of single sugar units or pairs of small sugar units bonded together. Complex carbohydrates (complex sugars) are compounds of long strands of many simple sugars linked together.

Now that you know what you shouldn't load up on, let's take a look at the foods you should eat. By now, you should be clued-in to which foods are rich in complex carbohydrates (pasta, grains, breads, cereal, legumes, and vegetables). Although they're actually made from hundreds—or even thousands—of simple sugars linked together, they react quite differently inside your body. After you ingest a complex carbohydrate (or starch), several enzymes break it down into its simplest form, called glucose.

Glucose is the simple sugar that your body recognizes and absorbs. All types of carbohydrate (simple and complex) must be broken down and converted into glucose before your body can absorb and use it for energy.

If all carbs wind up as glucose, why can't we just eat simple sugars? I've already touched on the first reason. Many simple sugars are nutrition zeroes, whereas complex carbs often provide phytochemicals, vitamins, minerals, and even fiber, depending on the food.


Hyperglycemia is a condition resulting in abnormally high blood-glucose (blood-sugar) concentration. Hyper means “too much,” glyce means “glucose,” and emia means “in the blood.” Hypoglycemia is characterized by abnormally low blood sugar. Here, hypo means “too little.” Diabetes mellitus is a disorder of blood-sugar regulation usually caused by the body's inability to either produce enough insulin or use it effectively.

In fact, your best complex carbs include vegetables and whole grains (not the white, refined stuff). Check out this comparison: a large baked sweet potato (high-quality, complex carb) versus a 20-ounce bottle of cola (simple carb). Although both provide about 280 calories, that's where the similarity ends. The sweet potato supplies potassium, magnesium, vitamin A, folic acid, vitamin C, and significant fiber, along with several other vitamins and minerals. And the cola—you probably guessed—provides zilch. Just plain sugar (18.5 straight teaspoons!). What's more, the sweet potato provides you with a fuller and more satisfied feeling. As you can see, eating complex carbs certainly does make a difference, even though it all ends up as glucose.

Another reason to choose complex carbohydrates is that the glucose created during digestion gets released into your blood more slowly. Simple carbohydrates are already broken down—they go straight into the blood, resulting in what is unofficially known as the “sugar rush”—whereas complex carbohydrates are larger molecules that must be broken down. As your body processes complex carbs, small glucose molecules are released into the blood over an extended period of time. This helps to regulate blood-sugar levels, especially in people who may have problems with their blood sugars (for example, people with hyperglycemia, hypoglycemia, or diabetes mellitus).

For the best regulation of problematic blood-sugar levels, choose carbohydrates that supply soluble fiber, including oatmeal, apples, sweet potatoes, beans, artichokes, grapefruits, squash, peas, brussels sprouts, and oranges.

Food for Thought

Some excellent sources of carbohydrates include fruits, vegetables, legumes, brown rice, barley, oatmeal, whole grain break, whole wheat tortillas, high-fiber cereal, and high-fiber crackers

How Much Carbohydrate Should You Eat?

As mentioned earlier, no less than 40 percent of your diet should consist of carbohydrates, specifically, complex carbohydrates. Most athletes and growing children and adolescents will need far more carbs than this, though. But no matter how high or low you go—always make the bulk of your carbs healthy ones.

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Excerpted from The Complete Idiot's Guide to Total Nutrition © 2005 by Joy Bauer. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.

To order this book visit the Idiot's Guide web site or call 1-800-253-6476.

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