A monounsaturated fatty acid is one in which one of the bonds between two carbon atoms in the hydrocarbon chain is a double bond (that is, a molecular bond in which two adjacent atoms share two electrons). This double bond replaces two hydrogen atoms, so the hydrocarbon chain is no longer “saturated” with hydrogen. Monounsaturated fats are less stable than saturated fats and require more enzymes to break apart in order to be used as energy than saturated fats do.
