Carbohydrates are a type of macronutrient, along with proteins and fats. Healthy sources of carbohydrates include vegetables, fruits, legumes and grains that have been minimally processed, while unhealthy sources of carbohydrates include processed and refined grain products, sugar, sodas and baked goods. It is important to get carbohydrates in your diet because they are the body's preferred source of energy.
How Carbohydrates Provide Energy
Carbohydrates exist in two forms: simple and complex. Simple carbs, known as sugars, are digested and used quickly in the body, and complex carbs, which are made up of more than one sugar, are broken down into simpler components and digested more slowly. All carbs are broken down into sugars, which trigger the release of the hormone insulin when they enter the bloodstream. Insulin directs the use and storage of this readily available energy.
Stored Energy and Direct Energy
If the carbs you eat cannot immediately be used for energy, they are stored as a compound called glycogen for later use. Glycogen is stored mostly in the liver and the muscles, ready to be broken down into glucose if immediate energy is not available. Any remaining glucose in the blood that cannot be stored as glycogen is eventually converted to fat and kept in the body as long-term energy storage.
Dietary Fiber Uses
The primary role of carbs is to provide energy to the body, but dietary fiber, a type of complex carbohydrate, is important for other reasons. Dietary fiber is indigestible, passing through the body in its whole form. Insoluble fiber, which is found in whole-wheat bread, legumes and many vegetables, is important for aiding the digestive system and preventing constipation. Soluble fiber, which is found in oatmeal, lentils and several fruits, helps lower cholesterol and blood sugar levels.
Risks of Insufficient Carbohydrates
While carbs are the most efficient source of energy, the body can get all of its energy requirements by breaking down proteins and fats. However, this means that your body must break down not only its fat stores, but also its lean muscle tissue to be used for energy. On a very low-carb diet, the body cannot perform high-intensity exercise, such as sprinting or weightlifting, as efficiently due to lower levels of muscular glycogen. You also risk constipation if you don't eat enough fiber.
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