In what form is body fuel stored as glycogen?

Glycogen is a polysaccharide that serves as a form of energy storage in animals and fungi. It is essentially a complex carbohydrate composed of long chains of glucose molecules. When the body has an excess of glucose, it converts it into glycogen for storage in the liver and muscles, to be used later when the body requires energy.

The storage of glycogen is crucial for maintaining blood sugar levels and providing energy during physical activities when glucose needs to be mobilized quickly. While glycogen does contain sugar in its structure, it is specifically categorized as a carbohydrate due to its molecular composition. Proteins and liquids do not serve as stored body fuel in the same way, making carbohydrate the appropriate classification for glycogen storage.