Yes, the heat is changing the qualities of oils. I read somewhere, that temperature more than 350 degrees F (in another places they say - 400 degrees F) is not good for you; the oil turns cancerogenic.

If I remember right, the high heat that is required for frying foods alters the chemical structure of the fat or oil and the body will not recognize it as a nutrient, but a toxin. I believe the only raw fats that can be used up to a medium heat without changing physical structure are coconut and palm oils... anything else will change structure.

There are some fats that are refined that can be used at a high heat; however their structure has already been changed through the refining process.

Using a heat of somewhere between 112 and 118 degrees is where foods start to lose their natural enzymes and vitamins. This is why it is always best to eat raw. If you do cook, as I do, try to use a medium heat and do not over cook anything, err on the side of undercooked.

Fats were one of the first things I studied in depth when I was attempting to get a blood pressure reading of 170/110 under control after BP medications sent my weight sky rocketing; I got mad at the doctors and ended up here. Hydrogenated fats, refined fats and/or oils (I see them as one and the same) consumption = high blood pressure among many other ills. Just about anything in a box will have some of these in them as they help prolong the shelf life of the product by using these oils (plastic), even those in a so called health food store. I will not touch canola, soybean, cottonseed, corn or most other refined oils. In the U.S. these oils and fats are almost always Genetically-Modified-Organisms crop produced and put into almost all processed foods along with Mono-Sodium-Glutamat (Natrium Glutamat) and a host of other things.

How was that for a simple answer? Steps off of box,

grz