In the dark ages of human health, very few people realized how unhealthy it was to use animal fats; vegetable oils; or, worst of all, butter to cook their food. Fortunately, our knowledge has advanced to the point of understanding the burden those substances can place on our heart, liver, arteries, and other organs. One of the first advances toward healthier eating was a reduction in the amount of oil used. This was achieved by baking or the use of a wok to prepare meals. Both are much better for your health than frying foods, but each still uses a small amount of cooking oil. A fairly recent development in the area of cookware and small appliances is the air deep fryer; a small appliance that completely eliminates the need for any type of cooking oil or butter.