This article is about lipid molecules. Fat may also refer to obesity or adipose tissue. FAT is an acronym.
Fat is one of the three main classes of food. It has many meanings, and the only good description is in technical terms. There are triglycerides, fatty acids, sterols, but "fat" may also refer to adipose tissue.
The main constituents of both animal fat and vegetable oils are triglycerides, that is glycerin molecules with three fatty acids attached. Nutritional fat is a mixture of many types of triglycerides, which differ in the length of their fatty acid chains, as well as the number and position of single and double bonds between their carbon atoms. Fat molecules contain only oxygen, hydrogen, and carbon atoms.
Vitamins A, D, E, and K are fat-soluble meaning they can only be digested, absorbed, and transported in conjunction with fats. Fats are sources of essential fatty acids, an important dietary requirement.
Fats play a vital role in maintaining healthy skin and hair, insulating body organs against shock, maintaining body temperature, and promoting healthy cell function. They also serve as energy stores for the body. In food, there are two types of fats: saturated and unsaturated. Saturated fat is a sort of a straight chain of carbon connected or bonded with 2 molecules of hydrogen. At the very beginning of this chain is a molecule of oxygen and a molecule of hydroxide. Unsaturated fat is the same thing with one major exception; some of those carbon atoms are not bonded with two hydrogen atoms so it becomes a very "fluid" state. Fats are broken down in the body to release glycerol and free fatty acids. The glycerol can be converted to glucose by the liver and thus used as a source of energy. The fatty acids are a good source of energy for many tissues, especially heart and skeletal muscle.