It's a good rule of thumb to avoid food that contains any kind of oil that is "partially hydrogenated." This is a relatively easy task to accomplish at home, but when eating in many of the thousands of New York restaurants, it becomes difficult to control. Should the health department subject restaurant to fines if they use this artery-clogging fat in their foods?
I can see why the mere mention of such a policy is being met with hostility. The smoking ban wasn't so much about the health of the smoker. It was about the health of the second-hand smoker. A smoker has the right to make the choice (albeit a stupid one) to damage his/her own health. He/she does not, however, have the right to damage the health of others. Since there's no such thing as second-hand fat, the argument supporting the trans fat ban is a little bit weaker. The guy sitting next to me shoving a doughnut in his mouth isn't going to make my arteries clog, so why should I bother him?
On the other hand, if such a ban would save lives in the end (like the seat-belt law), it can be argued that it's a good thing, especially since there are alternatives to these bad fats that are healthier and taste almost the same.