You shouldn't cook with extra virgin olive oil. It has a low smoke point and undergoes chemical changes at quite low temperatures. Refined light olive oil is ok. I use that for all my Italian recipes. Napolina is good. For my home-made oven chips, for which I need especially high temperatures, I use groundnut oil, which is neutral in flavour, doesn't break down and makes my chips lovely and crispy. Horses for courses. Just buy decent quality oil, avoid those massive bottles of cheap vegetable oil and forget the saturated/unsaturated claptrap.