The two main categories of fats are saturated and unsaturated.  Saturated fats are “saturated” with hydrogen atoms, meaning the carbon atoms are bonded to each other and to hydrogen, all with single bonds.  They are solid at room temperature.

Unsaturated fatty acids have at least one double bond between carbon atoms. One double bond creates a monounsaturated fat, and more double bonds create polyunsaturated fats.  The configuration of the double bonds in nature is “cis” in which the molecule is shaped like a boat, with the ends angling the same direction.  Once heated, the fatty acids may convert into “trans” configuration in which the molecule is shaped like a chair, with the ends in different directions.

Saturated fats will never be converted to trans fats. The more double bonds in the fatty acid, the more opportunities for the molecule to become trans. Unsaturated fats should, therefore, not be heated to high temperatures.  If you want to heat unsaturated oil, try using a monounsaturated fat.

  • Examples of monounsaturated fats are canola oil, olive oil, macadamia nut oil, grapeseed oil, sesame oil, peanut oil, corn oil, safflower oil, sunflower oil and avocado oil.
  • Examples of polyunsaturated fats are soybean oil, margarine, and fish oil.
  • Examples of saturated fats are butter, lard, ghee, suet, tallow, coconut oil, cottonseed oil, and palm kernel oil.

What is wrong with a trans fat?

Trans fats increase risk of coronary artery disease by raising levels of LDL (bad cholesterol) and lowering HDL levels (good cholesterol), due to hardening of the arteries.  It increases risk of heart attacks and has been liked to increased risk of breast cancer.  They also increase your risk of colon polyps and colon and rectal cancers, because they are not digested properly.

Try to reduce your intake of trans fats.