I make chips once a week using vegetable oil (usually rapeseed). I understand this type of oil is good for you normally because of the amount of monosaturates in it. But I think I read somewhere if you fry with it you change its composition by altering the way the hydrocarbons are put together, and then it becomes as bad as saturated fat?

Is this true? Should I just be using dripping in that case? Are rapeseed oil chips any healthier than ones cooked in lard?

Any oil gets worse for your health if you re-use it because it becomes more hydrogenated. Using it once is ok (although obviously frying anything is worse for you than grilling, baking etc.).

Oil also becomes more flammable each time it is re-used.

You may wanna have a read of this article that describes what happens :

http://www.medicinenet.com/script/main/art.asp?articlekey=47063

:gag:

I wont be giving up my chips, Im just curious and want to know why. Come on, someone must know.

Edit:
ooh posted too quickly! Thanks!

The article doesnt reach a straightforward conclusion though. It states at one point we might as well go back to frying with beef tallow (which I presume is US - speak for lard). Then at one point it says monosaturates are better... then clouds the issue by going on about polysaturates. It needs careful reading.