Essential fatty acids (EFA's) are "good fats" that are essential to every cell in your body. They play a critical role in immune, cardiovascular, and nerve function. They are called essential because our bodies cannot produce them, and therefore we must get them from the food we eat or from supplementation. Unfortunately, the food we eat is often not enough to supply the required amount of EFA's, as they are routinely processed out of most foods.
EFA's include Linoleic Acid, Omega-3 Fatty Acids, and Monounsaturated fats. These are considered the "good fats". They cannot be made by the body and must be supplied by our diet. You need approximately 2% of your daily calories as EFA's.