1. They are toxic products of OXIDATION
Vegetable and nut oils (canola, soybean, corn, sunflower, safflower, peanut, sesame, walnut, flax seed, etc.) are polyunsaturated, and as such, are subject to degradation into extremely toxic oxidation products when heated.
"Polyunsaturated" means they have carbon-to-carbon double bonds that are vulnerable to oxidation---oxygen readily attaches across these bonds in the chemical process called "oxidation." Even at room temperatures, these chemically “unsaturated” oils will oxidize slowly over time into toxic byproducts.
2. They are OUT OF OMEGA-6 / OMEGA 3 BALANCE
Vegetable oils are concentrated sources of Omege-6 lineoleic acid. Too much Omega-6 causes an imbalance with healthy, anti-inflammatory Omega-3’s.
3. They are CONTAMINATED WITH GLYPHOSATE
Corn and soy oils, in particular, as well as others, are produced with genetic engineering, which includes major exposures to glyphosate (aka "Roundup").
4. They are HIGHLY PROCESSED WITH HEAT & / OR CHEMICALS
Some vegetable oils, especially canola, grapeseed, and rice bran oil, are highly processed, which may include extracting with heat or solvents, and bleaching and degumming with chemicals.