<<Disclaimer: Verify this information before applying it to your situation.>>

Margarine is a nutritional disaster.  read how it is made and see if you
can ever face it again.  apart from everything else, the poly-unsaturates
are heated and thus go from cis form to trans form.  (That's why
mono-unsaturates like olive oil or canola ( or even gasp, butter) are
better for cookingFor people with a cholesterol problem, better to use
small amounts of butter.  margarine users, you have been conned.  Rather
than argue with me, check out

Beyond Pritikin by Ann Louise Gittleman
ISBN 0-553-05221-7

There is a lot in the mainstream health literature about the cis trans thing.

Art Raiche