All olive oils start out with a good balance of fats that lower bad cholesterol, but when you cook them really hot, that balance gets ruined — especially in oils that started with less of the good fats.

Some olive oils have a better balance of two types of fats (omega-6 and omega-3) than others — Picual, Manzanilla, Cornicabra, and Sensation are in the healthy range, but Arbequina and its blends are way off.

All olive oils have a lot of one type of antioxidant called alpha-tocopherol — but the amount varies: Cornicabra has the most, Manzanilla has the least.

The green color of olive oil comes from chlorophyll, and the amount varies a lot between types — Picual and its blends are the greenest, Manzanilla is the least green.

Some olive oils — like Picual and Cornicabra — hold up better when heated than others, like Arbequina and Manzanilla, because they lose fewer healthy compounds and form less gunk when cooked.

When olive oil gets super hot, it starts forming gummy, big molecules called dimers — and the amount depends on the type of olive oil: blends with more Arbequina make way more than those with more Picual.