"Designer oils" such as rice bran oil and grapeseed oil, often promoted as "healthy," are, in fact, highly toxic. Here's why: these oils are highly PROCESSED.
Also beware canola oil, which is popularly touted as a healthy oil. It is also in the HIGHLY PROCESSED category.
Processing is necessary to extract the oil from rapeseed (canola), rice bran, and grape seeds, and may include extraction with heat and solvents, as well as chemical bleaching, degumming, and deodorizing.
Because the raw oils have monounsaturated and polyunsatured components, when exposed to heat, they readily oxidize. Oxidized oils are toxic and highly inflammatory.
Avoid these oils, and use extra virgin olive oil (the highest grade olive oil, extracted with cold pressing without the use of solvents) instead.