Carbohydrates have been seen as the ultimate villain behind weight gain and the failure of diets. While there is some merit to these beliefs, the role of carbohydrates and their benefit to the body’s normal metabolic process is often misunderstood. Carbohydrates and their derivatives play major roles in organ systems, fertilization, blood clotting and, their main role, providing a source of energy.
Carbohydrates are one of the three main classes of food, along with proteins and fats. They come in several different forms, but the most common are sugars, starches and fibers. Carbohydrates are used by the body for energy; those that are not used immediately are stored either in the liver and muscles as glycogen or as fat.
A sugar molecule, which is made up of carbon, hydrogen and oxygen, is the basic building block of all carbohydrates. Starches and fibers are composed of chains of sugar molecules; some contain hundreds of chains. The amount of sugar chains and the body's ability to digest and absorb the sugars determines the type of carbohydrate. Foods containing one or two sugar molecules that are quickly digested are simple carbohydrates, and foods containing three or more linked sugar molecules that take longer to digest are complex carbohydrates.
Foods containing simple carbohydrates are often thought of as “bad carbs,” but many foods that contain simple sugars are very healthy, such as apples, blackberries, grapefruit, lemons and many other fruits. Simple sugars that are not healthy include soft drinks, table sugar, white bread, white pasta, candy and gum. A good rule for simple carbs is, if it contains natural sugar, it is probably good for you.
Complex carbohydrates are broken down by the body much slower than simple carbohydrates, so your body can use the energy as needed and less is stored in the body. Foods containing complex carbohydrates are mostly made of whole grains. These can be eaten in their raw form, such as oatmeal, bran, beans, corn, shredded wheat and brown rice. Other examples of complex carbohydrates are low-fat yogurt, spinach, onions, okra, zucchini, tomatoes, lentils, kidney beans, pears and carrots.
During digestion, the body breaks down carbohydrates into small molecules that can be absorbed into the blood stream. These small molecules, called monosaccharide, are carried to the liver and broken down into glucose. The glucose is then carried to the cells to provide energy for the body. Because the brain and nerve cells rely on glucose for energy and the body can store only enough glucose for about half a day, it is important that your body receive a steady supply of carbohydrates.