>Latest evidence is that oils identified as "healthy" such as sunflower or corn oil, produce "aldehydes" when heated. Aldehydes have causative links to cancer and other disease with levels up to 200 times as high as the "safe" dose in fried food. Whereas butter and even lard have much lower levels of aldehydes when heated. Olive oil has lower aldehydes and remains a safe option, or avocado oil if you can get it.

Have not checked new stuff, but my take on things was that refined sunflower oil was best for steaks, as it allows high temperature without adding too much of another taste. For salads and other stuff where you use unheated oil, use cold pressed plant oils, depending on your personal taste