Protein is a major structural component of cells and is responsible for building and repairing body tissue.
Carbohydrates are the main energy source for the brain. Your body would not be able to function without carbohydrates.
Fats are an energy source that when consumed, it increases the absorption of fat soluble vitamins , including vitamin A,D,E and K. 20-30% of your daily intake should come from fat.
Polyunsaturated fatty acids like the omega-6 fatty acids e.g linoleic acid (LA) has been found to lower blood cholesterol levels (LDL) and enhance HDL (the good cholesterol).