A carbohydrate is an organic compound such as sugar or starch, and is used to store energy. Carbohydrates are built of small, repeating units that forms bonds with each other to make a larger molecule. In the case of carbohydrates, the small repeating units are called monosaccharides
In the mid-1800's, German chemist Justus von Liebig was one of the first to recognize that that the body derived energy from the oxidation, or when a material gives up electrons as a result of combining with oxygen, of foods recently eaten. He also declared that it was carbohydrates and fats that served to fuel the oxidation - not carbon and hydrogen as was once thought.
The appearance of carbohydrate molecules differentiate depending on the type. Monosaccharides and Disaccharides are relatively small molecules. They are often called sugars. Other carbohydrate molecules, such as polysaccharides, are much larger.
Foods high in carbohydrates are an important part of a healthy diet. Carbohydrates provide the body with glucose, which is converted to energy used to support bodily functions and physical activity. Carbohydrate quality is important, though; some types of carbohydrate-rich foods are better than others.
Carbohydrates are found in a wide array of both healthy and unhealthy foods- bread, beans, milk, popcorn, potatoes, cookies, spaghetti, soft drinks, corn, and cherry pie. They also come in many forms. The most common and abundant forms are sugars, fibers, and starches.
Most carbohydrates come from foods of plant origin. The food-making process in plants produces sugars. The major simple carbohydrates or sugars are glucose, maltose, fructose, and sucrose which come from plants. Sugar molecules can combine, forming larger molecules called starches, or complex carbohydrates. Plant cells store excess energy in molecules of starch.
The role of carbohydrates in the body includes providing energy for working muscles, providing fuel for the central nervous system, enabling fat metabolism, and preventing protein from being used as energy. Carbohydrates are the "preferred" source of fuel for muscle contraction and biologic work.