Fat is an important nutrient that is essential to normal body function. Fat supplies us with energy, it is our means of storing energy and it allows other nutrients such as fat-soluble vitamins to function efficiently. Every cell of our body is surrounded by a fatty layer (called a ‘bi-layer’), otherwise known as a fatty acid membrane. The type of fat we in our diet becomes part of this membrane and has major influences on the function of that cell (imagine, for example, if you ate only pies, donuts and chips, your cell membranes would be made up of sticky, rigid hydrogenated fats!) Different fats also have different functions. Some are easily used as fuel, some are mainly structural and others have a more specialised role, influencing how our brain and body function.
Chemically, fats are usually known as fatty acids and the majority of edible fat is in the form of triglycerides (three fatty acids on a glycerol back bone if we’re talking chemistry terms). There are two major sources of fat, however: animal and vegetable. When fat is at room temperature it can be in liquid or solid form: those which are liquid at room temperature are usually refered to as oils and, when solid at room temperature, are referred to as fats. Oils, as a rule, tend to be derived from plants and fat is most often derived from animals.