One of the most common questions I get about health and nutrition concerns what fats and oils to use for cooking. This Kitchen Guide to Fats and Oils lays out the best choices for high heat cooking, those best left unheated, and which to avoid.
The chemical structure of fats determines how it is best used. Fats are made up of a combination of three main kinds of fatty acids: saturated, monounsaturated, and polyunsaturated. Fatty acids are chains of carbon atoms that have hydrogen atoms attached.
Saturated fats are highly stable in their chemical structure. It’s carbon chain is saturated with hydrogen atoms, which resist oxidation even at high temperatures. These are found mostly in animal fats and tropical oils.
Monounsaturated fats have a carbon chain missing 2 hydrogen atoms and has one “mono” double bond so it is not saturated by hydrogen atoms. The double bond creates a less stable structure that keeps the fats liquid at room temperature. These are found in olive oil, avocados, and nuts.
Polyunsaturated Fats (PUFAs)
Polyunsaturated fats are missing several hydrogen atoms in the carbon chain and contain two or more “poly” double bonds. These are the least stable and oxidize easily when exposed to heat and light forming damaging free radicals that inflame the body. These are found in vegetable oils, rice bran oil, grape seed oil, corn, soy, sunflower, and safflower oils.
PUFAs are the worst choice for cooking oils because of its unstable structure, highly processed nature, and because they are high in omega 6 fatty acids. American diets are already too high in pro-inflammatory omega 6 fats. This increased inflammation is associated with diabetes, obesity, cardiovascular disease, auto-immune issues, infertility, and cancer.
The best option is to choose fats from sources that nature provides and the least processed as possible.