Carbohydrates, such as sugar and starch, for example, are broken down into glucose. Glucose constitutes the body's principal energy source. Glucose can be used immediately as fuel, or can be sent to the liver and muscles and stored as glycogen. Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in humans, animals, fungi, and bacteria.
Glucose comes from the Greek word for "sweet." It's a sort of sugar you get from foods you eat, and your body uses it for energy.
