That's not true, another human myth.
here is the paper, TLDR: olive oil retains most of its nutritional benefits even when heated in high temperatures.
https://pubs.acs.org/doi/abs/10.1021/jf020506w
go for healthy fat! :)
Unsaturated fats are at a much higher risk of oxidation, which is why cooking with canola oil (7.4% saturated, 28.1% polyunsaturated), for instance, is so dangerous – without the hydrogen armor around the carbon backbone, the fat is at high risk for oxidation, after which point it becomes toxic.
The study you linked to even alludes to this danger: > It is worth noting that all the heating methods assayed resulted in more severe polyphenols losses and oil degradation for Arbequina than for Picual oil, which could be related to the lower content in polyunsaturated fatty acids of the latter olive cultivar. These findings may be relevant to the choice of cooking method and olive oil cultivar to increase the intake of olive polyphenols.
Suggesting that if you want to cook at higher heats with olive oil, you should search for one with an exceptionally low polyunsat content.
Greeks have been frying french fries in olive oil since, well, the coming of potato to Europe... No casualties yet.