margarine, hydrogenated fat (which coincidentally is often in margarine), and high fructose corn syrup are all horrible items.
If I eat a food product that has a high amount of margarine, I get physically ill and will sometimes even vomit. But, I can eat a dinner roll and use 4-6 pats of butter (depending on the size of the roll) and no problem. Which tells me that margarine is bad bad bad!