The use of heat and its negative effects on the food we eat is highly variable from food to food. The bonds inside seed oils are less stable when exposed to heat, as opposed to something like tallow. However tallow still has a cooking temperature that shouldn’t be exceeded, but I believe it’s higher than seed oils. No sources, but I’ve dug into this a bit. There’s a good YouTube video that shows how seed oils are made. It’s like a “How It’s Made” episode but not that actual show. In general I don’t believe seed oils are healthy for you, but I think it gets over blown. I avoid them when possible but I don’t sweat it if I’m out to eat and they cook with seed oils. Gotta enjoy life. The anxiety of avoiding every single seed oil can’t be healthy either.