Glycogen is a nutrient complex homopolysaccharide. Glycogen is the main stored food in the animal body. Glycogen is stored in the liver, muscles, brain and stomach of vertebrates. But the liver has the most. Human liver contains about 100-120 grams of glycogen. Cyanobacteria or blue-green algae and some fungi (yeasts) have glycogen as stored food. Glycogen is called animal starch. French scientist Claude Bernard (1857) discovered glycogen.