Fats are composed of the elements carbon, hydrogen and oxygen. The proportion of hydrogen to oxygen atoms is consistently higher than 2:1.
Fats belong to a group of biomolecules called lipids. These organic substances consist of three fatty acids and one glycerol.
Fatty acids are long chains of hydrocarbons with a carboxyl group at the end of the chain. Each hydrocarbon chain may contain between 10 and 30 carbon atoms, although the typical range is 12 to 18 atoms. For example, the saturated fat palmitic acid has the chemical formula CH3(CH2)14COOH. This fatty acid has 16 carbon atoms, including the one from the carboxyl group COOH.
Glycerol molecules contain three carbons, where each carbon atom bonds to the first carbon atom of three fatty acids to form a fat molecule. This process occurs through the loss of water molecules.