In the health community, we’re told we should use certain oils to cook with over others. Not many people explain why some oils are better than others. Instead of taking the ‘everybody knows’ approach such as, processed rapeseed/canola oil is better than real butter? Um, no.
There are many types of cooking oils/fats and their smoke points vary (see image below from BalancedBites). The smoke point of oils is the temperature when fats begin to breakdown. Mary Enig, Ph. D., author of Know Your Fats states, “If the collection is liquid at ambient temperature, it’s called an oil; if it is solid, it’s called a fat.” Oils/Fats have a fatty acid composition in the form of Polyunsaturated Fatty Acids (PUFA), Monounsaturated Fats (MUFA), Saturated Fatty Acids (SFA), and other (usually insignificant amounts).
Even though some of these look like great choices for high temperatures based on smoke point, that’s not always the case. The processing of how these oils are created are a huge factor, as are their stability.
Most of the oils in the infograph, under the red heading, are created by an unnatural chemical process. The majority seed oils are extracted using a solvent, commonly hexane, after being crushed. Then they are degummed, neutralized, dewaxed, bleached, filtered, and deodorized. It’s a very unnatural process.
One of my favorite oils for medium to no heat is cold pressed extra virgin olive oil. It has a high smoke point, which is good for medium heat (explaining why only medium in next paragraph)… when it’s 100% pure. Most olive oils are actually cut with lower grade oils (extra source) and reduce their smoke point. Not only that, but they also can be rancid, which is the taste most Americans are used to. You should buy olive oil brands that are highly reputable and in a dark glass container. This makes sure you get a real, non-rancid olive oil.
Rancidity is mostly based on oxidative stability, which shows how resistant the fats are when reacting to oxygen. Polyunsaturated and monosaturated fats oxidize easier than saturated fats; PUFAs are the most prone to oxidation, followed by MUFAs. In other words, the chemical structure of unsaturated fats are delicate; saturated fats are less delicate and more stable (source). This is the reason why olive oil should only be used for medium to no heat applications, as olive oil is high MUFAs (see infograph above).
My favorite oil to use for high heat is coconut oil. As coconut oil is mainly saturated fat, it takes a lot more effort for it to go rancid.
When oils go rancid, they create inflammation in the body. Inflammation leads to many, many, many health problems (including being easier to sunburn).
Note: There is varying information about the exact fatty acid makeup of all the oils/fats. There are all within a few percentages though.