Olive oil is the best to use for health. Canola oil was originally an industrial oil made from the poisonous seed called the "rape" seed. The seed was geneticly modified to not be poisonous.... and therefore "experts" said it is ok for human consumption now! The WORST oil for health is anything hydrogenated. When an oil is hydrogenated, it is heated and hydrogen is bubbled through it. This converts an oil to resemble PORK FAT (molecular structure). Margarine butter is 100% hydrogenated oil. It is deadly (clogs your arteries). Some of the oils were invented during world war 2. The Germans needed fuel for their tanks and allied bombers targeted fuel depots. German scientists discovered that diesel engines could run on vegetable oils when processed! German tanks were FAR superior to allied tanks. We defeated them by cutting off their FUEL supply.
If you want to research this subject, I suggest you look for the works of a lady named Dr Johanna Budwig. She is Germany's premier biochemist and holds a Ph.d in Natural science. In an article she wrote, she recommends the benefits of Flaxseed Oil.... and warns against hydrogenated oils. (Healthy Cell News... Spring/Summer 1998)
Be carefull of what oils you consume. The giant agri-business corporations don't care about your HEALTH. Their main concern is MONEY. As a result, many people are eating oils originally intended to be fuels for tanks!