A natural organic compound that consists of a carboxyl group (oxygen, carbon and hydrogen) attached to a chain of carbon atoms with their associated hydrogen atoms. The chain of carbon atoms may be connected with single bonds, making a ‘saturated’ fat; or it may contain some double bonds, making an ‘unsaturated’ fat. The number of carbon and hydrogen atoms in the chain is what determines the qualities of that particular fatty acid. Animal and vegetable fats are made up of various combinations of fatty acids (in sets of three) connected to a glycerol molecule, making them triglycerides.