Why is an element in it neutral states has no enthalpy change

When physical or chemical changes occur, they are generally accompanied by a transfer of energy. The law of conservation of energy states that in any physical or chemical process, energy is neither created nor destroyed. In other words, the entire energy in the universe is conserved. In order to better understand the energy changes taking place during a reaction, we need to define two parts of the universe, 

Explanation:

A saturated fat is a type of fat in which the fatty acid chains have all or predominantly single bonds

Unsaturated fats are derived from plants and some animals. They contain at least one double bond in their fatty acid chain.