Fat is one of the 3 main components of nutrition and at 9 kcals per gram the most concentrated form of metabolic energy. Protein and carbohydrates only have 4 kCals per gram. Essential fatty acids are very important for your skin, your hair, your organs etc. So it would not be a good idea to keep your fat intake as low as possible. Besides, the vitamins A, D, E, and K are fat soluble, meaning they can only be digested, absorbed, and transported in conjunction with fats. Basicly the fats are broken down inside the body to release glycerol and free fatty acids. Find more sports nutrition related topics at the nutrition main page.