I think we need to be clear on what trans fat is.
trans fat is a fat substitute which has a longer shelf life. It is cheep to use and produce.
This is like trying to market sacarin as sugar and not telling anyone.
Usually longer shell "life" goes together with lower nutritional value and more problems with digestion.
In other words, if it is not good for bugs, it is not good for you.
Uh, I think most people, if not all, know that transfats are bad to eat. And I believe the food labeling laws already require the transfats to be listed.
And in a restaurant, all you have to do is ask. If they can't tell you what the transfat level is in a food, don't order it.
"Trans fats" include things like "partially hydrogenated soybean oil." Partial hydrogenation reduces the number of double bonds in the oil, raising the melting point. It also introduces some trans- double bonds into molecules which are normally all cis-. It is the basis for the modern production of inexpensive margarine. The campaign to ban trans fats is a campaign to ban partially-hydrogenated plant oils. I guess we can go back to the original margarine, which was made from clarified beef fat. That should make the vegans happy.
Trans fats are not poisonous; they are merely not the best things in the world to eat in large quantities. The same can be said of beer, chicken eggs, and jabanero peppers. Perhaps we should ban them.