We already know that we need fat for many reasons, but we only need good fat. This is especially important while choosing cooking oil. We should avoid polyunsaturated fats that are harmful when heated. Your best choice is extra virgin olive oil. It's been used for thousands of years and is a main ingredient of the healthy Mediterranean diet. Other useful oils are coconut, canola, avocado and flax seed oil. Choose from cold-pressed oils made without the use of heat or chemicals. Not all oils are suitable for high heat cooking, but all can be used as salad dressings. All cooking oils are to be kept in a dark place away from heat to keep them fresh.