There's some disagreement out there as to whether high temperature alone can change a fat into a trans-fat. Schwartzbein says yes, but the Eades, quoting studies by Dr. Mary G. Enig of the University of Maryland, say that the process also requires a chemical catalyst.

Unfortunately, it seems that heating unstable oils (like polyunsaturates) to the kind of high temperatures generally used for frying does turn them into lipid peroxides -- fats that have been damaged by free radicals and can themselves react with other substances (like the iron in your system) to produce the hydroxyl radical - the most dangerous of the free radicals. [PPLP pgs 115, 123-24] So it's probably best not to cook with your Smartbalance, but it's fine to put it on your veggies because you won't be exposing it to enough heat to damage it that way.

--Ruth