Fats are good. They get a bad wrap, but we need them. But what happens to fat when it’s cooked?
Heating olive oil actually causes a negative chemical change in the fatty acids, releasing ‘toxic oxygenated aldehydes’. These TOA’s cause oxidative stress (basically impairing your ability to repair damaged cells) and increase your body’s predisposition to degenerative diseases. This is a bad thing.
Wikipedia tells us that “In humans, oxidative stress is involved in many diseases. Examples include atherosclerosis, Parkinson’s disease, heart failure, myocardial infarction, Alzheimer’s disease, fragile X syndrome and chronic fatigue syndrome.”
If you must heat oil, at least use Extra Virgin varieties, which have been shown to produce less ‘toxic oxygenated aldehydes’ (Elhuyar Fundazioa (2005, June 17). Toxic Substances In The Oxidation Of Fats And Oils. ScienceDaily.).