Many so-called chefs are now using olive oil, instead of corn oil or vegetable oil for stir frying vegetables. They certainly have no knowledge of some of the critical properties of these different types of oil. The following properties of these different types of oil make corn oil and vegetable oil a better choice than olive oil for cooking:
First, olive oil contains saturated fat (in addition to unsaturated fat), such as palmitic acid which is also contained in most meat. So, eating olive oil does not prevent the problems caused by eating animal fat. Saturated fat is considered a possible cause of cardiovascular diseases. Neither corn oil, nor vegetable oil contains any saturated fat.
Second, olive oil becomes part of the diet of many people in the world population until only recently. Most of our ancestors had never used olive oil. It is doubtful that we can adapt to a large quantity of this new item in our diet without having any potential problems.
Third, olive oil has a very low boiling point due to the presence of saturated fats. A low boiling point results in a lot of smoke even at relative low temperature. On the other hand, corn oil and vegetable oil only contain unsaturated fat and hence have much higher boiling points, resulting in much less smoke. Cooking smoke not only makes your kitchen greasy and dirty. A lot of cooking smoke will also have harmful effects to the cook, especially to the lung, in the long-run.
Finally, olive oil is much more expensive. It is just not worth it.
Olive oil is good for salad only because it is thicker, due to its higher viscosity. When it comes to cooking, olive oil is a poor choice!