Even though avocado oil looks healthy, it has enough bad fat in it to break down easily when heated.

Olive oil’s polyunsaturated fat content (11%) renders it more susceptible to thermal oxidation than animal fats with lower PUFA content (e.g., tallow, ghee <2%).

Olive oil, due to its 11% polyunsaturated fatty acid content, exhibits greater oxidative degradation under heat compared to animal fats with <5% polyunsaturated fat content.

When you heat oil, the good unsaturated fats break down and disappear, leaving behind more of the saturated fats — so the oil becomes more saturated over time.

When you fry with these oils over and over, they react with heat and moisture and start breaking down into chemicals that signal the oil is going bad.