Fats are essential constituents of food for many animals. Fats contain twice as many calories as carbohydrates. We store fats in specialized connective tissues, which not only act as energy reserves but also insulate the body and cushion the organs.
Fat:

* Provides a source of energy.
* Makes diet palatable.
* Provides basic building blocks for cell structure.
* Provides essential fatty acids.
* Acts as a carrier for fat soluble vitamins (A, D, E & K).

However, too much fat especially fat of animal origin, is bad for you causing obesity, blocked arteries & heart disease. Foods rich in fat include butter, margarine and cooking oils.