However, one must understand that the notion, 'oil is fat, and fat is bad' may not be true always. In fact, fat is a nutrient required by the body to absorb certain vitamins and minerals. More than fat, it is the particular type of fat that decides the nutritional value of cooking oil. You may be aware about the nutritional facts of popular oils such as olive oil, canola oil, but cottonseed oil and peanut oil rarely top the list of popular healthy cooking oils.