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.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
