Saturated and Unsaturated Fats

Some fats are solid at room temperature, while others are liquid. The liquid fats we usually refer to as oils. Whether the fats are solid or liquid depends on the fatty acids that make up the fat molecules (see sidebar).

Fatty acids consist primarily of long chains of carbon atoms to which hydrogen atoms are attached. If a fatty acid chain contains as many hydrogen atoms as it can possibly hold, it is called saturated. If the chain has empty spaces that could hold more hydrogen, it is called unsaturated. (One or more places along the carbon chain can lack hydrogen atoms.) Saturated fats are solid at room temperature, while unsaturated fats are liquid.