Fatty acid chains have single bonds and all the hydrogen and carbon atoms they can hold. This makes them stable.

The single bond structure creates a straight, stiff chain which is more stable than unsaturated fats.

They are usually solid at room temperature; therefore, they do not combine readily with oxygen.

There are two types, animal based and plant-based.

Animal based saturated fats are made of long chains. 

Plant based saturated fats are made of short and medium chains.

UNSATURATED

Fatty acid chains have one or more double bonds and this makes them more liquid and less stable.

Monounsaturated fats have one double bond.

Polyunsaturated fats have more than one double bond.

There are two types, Cis and Trans

Cis have a bend in the molecule, take up more space, and are found when the fat is in its natural state,

Trans are created when liquid oil is subjected to hydrogenation. Through this process a Cis molecule, with a bend, is transformed into a straight molecule and is more stable.