Classifying Carbohydrates: Refined and Recommended

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Despite what no-and low-carb diets prescribe, carbohydrates are an essential source of fuel for the body as well as an aid for organs to perform necessary functions. Read on to learn which carbs can facilitate a great athletic performance and which can hinder it.

What are carbohydrates?
Carbohydrates provide the body's fuel for physical activity and proper organ function. The liver turns all carbohydrates, except fiber, into glucose (blood sugar). The entire body, especially the brain and nervous system, uses the glucose for energy. More than being an energy source, carbs regulate glucose levels in the blood, prevent protein sources from being used for immediate energy, break down fatty acids and prevent ketosis (breakdown of fat stored for energy).

Carbs come in a variety of forms:

  • Starch—Reserve food energy; largely found in plants
  • Glycogen—Stored in the liver; functions as reserve energy
  • Fiber—Cannot be broken down into sugar molecules; goes through the body undigested, which is why foods are now labeled with "net carbs"

What are the different classifications?
There are two types of carbohydrates: simple and complex. Natural simple carbohydrates that contain vitamins and minerals include fruits, milk, milk products and vegetables. But, simple carbs can also be found in processed and refined sugars such as candy, table sugar, syrups (not including natural syrups such as maple) and regular soft drinks.

Complex carbohydrates can be found in starches and dietary fiber.

Good sources of starches include:

  • Breads—whole-grain and white
  • Breakfast cereals—cooked and ready-to-eat
  • Flours—whole-grain and white
  • Pastas
  • Barley and rice
  • Legumes—dried peas, beans and lentils
  • Starchy vegetables—potatoes, butter beans, corn, sweet peas, lima beans and navy beans

Good sources of dietary fiber include:

  • Whole-grain breads and other grain bakery products
  • Whole-grain cereals—cooked and ready-to-eat
  • Legumes—kidney beans, lima beans, navy beans and split peas
  • Fruits, especially the skins and edible seeds
  • Nuts and seeds

What carbs should athletes avoid?
Fiber slows the absorption of other complex carbs into the blood stream and slows the digestion of these foods in the stomach. Athletes looking to increase their body's immediate access to glucose should avoid foods high in fiber right before a competition. The energy won't be available quickly and the food in the stomach could cause discomfort.

How quickly does the body absorb carbohydrates?
The glycemic index measures how fast and how far blood sugar rises after eating food that contains carbohydrates. High glycemic food raises blood sugar levels quickly. Examples include potatoes, corn, carrots, bagels, white bread and sports drinks.

What are the potential drawbacks for athletes from reduced carbohydrates diets?
Conventional and scientific wisdom says carbohydrates are the most efficient fuel for your body during strenuous exercise. So, most athletes eat as many complex carbs as they can. But, an athlete's need for protein is still greater than that of a couch potato, because both muscle-building activities and aerobic exercise burn protein for energy. However, these increased protein needs can be met easily without resorting to a low-carb diet.

If you and your parents decide a reduced carbohydrate diet is for you, there are considerations to be made when in season for a sport. If your sport requires a great deal of endurance for competition (cross-country, distance track events, distance swimming and triathlons) you may need to undergo a carb-loading phase before competition. In a low-carb diet it is still best to try to include fruits, vegetables and whole-grain carbohydrates every day. These foods have vitamins and minerals essential to good health.

How many and when should an athlete eat carbs?
Athletes should try to avoid simple carbohydrates and those complex carbs with a high glycemic index. That leaves complex carbs with low glycemic indices. About 60 percent of your calories should be from carbs. This means if you average 2,000 calories a day, about 1,200 (or 300 grams) should be from carbohydrates.

To check the glycemic index of your favorite foods, visit

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