Fats are high energy molecules that assist in a growing organism. There is a lot of calories in fat that can be used for growth.When metabolising fat it produces carbon dioxide, water, and ATP. Sugars and/or starch is useful in the same method, they provide calories necessary for a seed or baby animal to grow. The starch can be cleaved into more managable sugars, and the sugars used in glycolysis and then the products of glycolysis used in the citric acid cycle. Used together an organism would have water from the fat that can be used to hydrolyze the sugars that it would consume to produce ATP.
Secretion of glucagon from the pancreas results in break down of glycogen, which causes an increase in blood glucose levels. Glucagon is a hormone that is produced by alpha cells in a part of the pancreas known as the islets of Langerhans. It is released in response to low blood glucose levels and to events where the body needs additional glucose, such as in response to vigorous exercise. It stimulates break down of glycogen, activates gluconeogenesis (the conversion of amino aids to glucose) and break down of stored fats into fatty acids. This results to high blood glucose levels.
Friedrich Miescher in 1869
