The smoke point of an oil, is the temperature at which the oil breaks down. This is the point where flavour and nutritional properties begin to be lost. Olive oil is wonderful for cooking and will not lose its properties when heated. Olive oil is very resistant with a high smoke point of 210oC, and will not degrade as quickly as other oils with repeated heating. Oils that do not have this quality of olive oil become hydrogenated or saturated on heating, loosing their nutritional benefits and actually becoming harmful to the body.
In Greece olive oil is used for all types of cooking from frying, cooking, grilling and baking. Butter is very rarely used in Greek cuisine.