Carbohydrates are your body's preferred energy source and are found in the forms of starch, sugar and fiber. Digestion begins in your mouth where the process of chewing mechanically breaks food into small pieces. Enzymes in the saliva initiate chemical digestion. When you swallow, partially digested carbs travel down your esophagus to the stomach with little additional digestion. From there, carbohydrates move into the small intestine where enzymes released by the pancreas break them into simple forms to be absorbed into the bloodstream. Fiber is indigestible and passes through your gastrointestinal tract without being broken down.