The Institute for Medicine has determined that there are no safe levels at which to consume trans fats. Over the years, scientific research has determined that they are a much more dangerous source of fat than naturally occurring ones. Trans fat can both raise the levels of "bad" cholesterol while lowering levels of "good" cholesterol.
Artificial trans fats — created by the process of partially hydrogenating a liquid fat (like vegetable oil) into a solid fat (like margarine) — fall under this FDA ruling. What are some other common sources? It's in some ramen noodles, fast food, baked goods, chips, frozen pizzas, and tons of other foods. (There are naturally occurring sources of trans fat; it makes up approximately 2% to 5% of all body fat in cattle and sheep. And, it's also present in relatively low levels in their meat and milk. But, the ruling will apply only to artificial sources.)
Though the FDA began requiring large producers to list artificial trans fats on labels back in 2006, greatly decreasing the number of sources of artificial trans fats, it has been a mainstay in many other widely available, fast-and-cheap foods.
In order to avoid the ban, food manufacturers would have to prove that trans fats are safe for consumption — a difficult task given the huge amount of scientific literature already out there that says just the opposite. The foods at the center of this battle won't likely be totally eliminated, but they will have to change their recipes in substantial ways. Many food brands — including major ramen brands like Top Ramen — have already voluntarily eliminated trans fats, but some have not. Goodbye, to many foods, as we know them. We're looking forward to a healthier future of snacking, please. (The New York Times)