Fats
Fats substances are made up of ester of fatty acids. Fats are generally obtained from plant and animal sources. Fats with high energy give more calories and also take more time to digest.
Fats are the source for composing and maintenance of regular cell membranes of the body. They are also needed for maintaining the health of skin and hair. The fatty acid that the body cannot manufacture and have to get from a proper diet are called essential fatty acids. For example, Alpha-linolenic acid (Omega -3 fatty acids).