Carbohydrates (or “carbs,” for short), sometimes called sugars or starches, are the human body's main source of glucose. Once carbs are converted to glucose and enter the bloodstream, the pancreas secretes the hormone insulin, which enables the body's cells to use the glucose for energy. Glucose is also essential for central nervous system functioning.

Fiber is considered a carbohydrate, but unlike sugars and starches, it doesn't have an appreciable impact on blood sugar levels. When you're looking at the nutrition facts label on packaged food, you'll see that dietary fiber is included in the total carbohydrates listed, but is also broken out as a separate measurement so you can see how fiber-rich the food is.

Fiber is beneficial to both children and adults for a number of reasons. First of all, fiber doesn't break down significantly in the gastrointestinal tract. That makes it bulky and therefore filling. So a little bit of fiber goes a long way towards making you feel full. Second, fiber promotes both heart and gastrointestinal health. Insoluble fiber, found in whole grains like wheat bran and fibrous vegetables, keeps the colon clean, while soluble fiber — found in beans, berries, nuts, and seeds — soaks up the bile acids that convert to cholesterol.

Recommendations for Total Carbohydrates

The USDA- and FDA-recommended daily value for carbohydrates is 60 percent of total calories. DRI 2002 recommends that 40 to 65 percent of daily calories come in the form of carbohydrates. For children between age one and eighteen, the RDA for carbohydrates is 130 grams.

Some clinical studies have indicated that regularly consuming high glycemic index carbs can reduce good cholesterol, increase bad cholesterol, and raise long-term blood glucose levels. Yet it is also unhealthy to consume too few dietary carbohydrates each day, as the body needs carbohydrate-generated fuel to function properly. See Chapter 7 for more information on the glycemic index of carbohydrates and controlled-carb and low-carb diets.

Recommendations for Fiber

Look for whole-grain breads and cereals, such as bran, which are kid-friendly and versatile food choices with plenty of fiber. Other good sources of dietary fiber include fresh fruits (with the skin on), popcorn, brown rice, and root vegetables. Children and adults should have 20 to 35 grams per day.

The DRI 2002 recommends that children between the ages of one and three maintain an average intake of 19 grams of fiber daily. For children four to eight, the recommendation is 25 grams daily. Boys aged nine to thirteen should be eating 31 grams of total fiber each day; from ages fourteen to eighteen, they should have 38 grams daily. Girls from age nine to eighteen should consume 26 grams of total dietary fiber daily.