The smoke point is not a reliable indicator
for the stability of edible oil
There is no scientific basis for the common misconception that you shouldn't cook with extra virgin olive oil. Many of the myths surrounding cooking with olive oil have to do with the smoke point. Many people mistakenly believe that one should only cook with oils that have a high smoke point.
The smoke point of an oil is defined as the temperature at which the fat produces a thin, continuous stream of bluish smoke under controlled circumstances. Although smoke point was thought to indicate an oil's safety and suitability for cooking, new research has shown that this is not the case. An oil's smoke point does not correlate to its performance and stability when heated. Rather, the factors that predict an oil's safety and stability at high heat are the percentage of polyunsaturated fats (the lower the better) and the extent to which the oil has been refined (the less the better). Extra virgin olive oil, which has a low concentration of polyunsaturated fatty acids and is not refined at all, turned out to be the best oil for cooking.
Extra virgin olive oil was the top performing oil, but regular olive oil also performed better than most seed oils. According to Leandro Ravetti, one of the researchers on the study, this is for three reasons:
1) the oleic acid composition of olive oils;
2) the fact that regular olive oil is fortified with some (usually around 15-20%) unrefined extra virgin olive oil; and
3) the fact that the refining process for olive oil is carried out under relatively gentle physical conditions compared to those used for seed oils, which are extracted with solvents and therefore require aggressive refining at very high heat.
The infographic below explains how the study was conducted and its conclusions. Finally, if you love olive oil, you can now confidently cook with it - even with extra virgin olive oil - like any other oil.