Experts say there really is no exact parallel to trans fat; the ingredient is unique in just how bad it is for you, how common it was in the food supply and how unessential it was for nutrition. But there are a few candidates for the "next trans fat," although they will probably be harder to regulate, experts said.

On Tuesday (June 16), the Food and Drug Administration ruled that trans fat is not "generally recognized as safe" to be added to food, meaning that the ingredient will now be considered an illegal food additive. Companies have three years to either remove trans fat from their food, or petition the FDA for permission to use the additive in specific cases.

Banning trans fat was a pretty easy decision to make, because of how bad it is for health, said Thomas Sherman, an associate professor of pharmacology and physiology at Georgetown University School of Medicine in Washington, D.C. Studies show the ingredient not only increases levels of "bad cholesterol," but also lowers levels of "good cholesterol" and increases levels of fats in the blood, which in turn increase resistance to the hormone insulin.