According to law of thermodynamics, energy can neither be created nor can be destroyed. It can be converted from one from one form to another.
Hence, the food that we eat is a source of energy. The chemical energy stored in food, is utilized for various function of body such as breathing, walking, talking, etc. Now, if you body does not have chemical energy, if will not be able to perform various task, which are essential for living.
Due to this, absence of chemical energy in the body, can will eventually lead to death.
