I think canola oils is absolutely one of the worst oils. Right now I use a
little olive oil and sometimes coconut oil. But if it came down to it, I
would use butter over canola oil any day. The problem with (raw) butter
isn't that it is bad for you, but that animals incase toxins in their fat
just like people do. So unfortunately, butter is often high in toxins
because of this. Otherwise, raw butter is somewhat natural compared to the
highly, highly processed canola oil (clue: deodorization means heat the hell
out of it). Of course, pasteurized butter is processed and heated, and is a
different story all together.

Jay

http://www.westonaprice.org/know_your_fats/oiling.html

Canola oil, processed from a hybrid form of rape seed, is particularly rich
in fatty acids containing three double bonds and can contain as much as 50%
trans fats. Trans fats of a particularly problematical form are also formed
during the deodorization of canola oil, although they are not indicated on
labels for the liquid oil.12a

Certain forms of trans fatty acids occur naturally in dairy fats.
Trans-vaccenic acid makes up about 4% of the fatty acids in butter. It is an
interim product which the ruminant animal then converts to conjugated
linoleic acid, a highly beneficial anti-carcinogenic component of animal
fat. Humans seem to utilize the small amounts of trans-vaccenic acid in
butter fat without ill effects.

But most of the trans isomers in modern hydrogenated fats are new to the
human physiology and by the early 1970's a number of researchers had
expressed concern about their presence in the American diet, noting that
their increasing use had paralleled the increase in both heart disease and
cancer. The unstated solution was one that could be easily presented to the
public: Eat natural, traditional fats; avoid newfangled foods made from
vegetable oils; use butter, not margarine. But medical research and public
consciousness took a different tack, one that accelerated the decline of
traditional foods like meat, eggs and butter, and fueled continued dramatic
increases in vegetable oil consumption.