Are the States Preempted from Banning Trans Fat?
The states are clearly preempted on the labeling requirements for trans fat. The Federal Food, Drug, and Cosmetic Act (FDCA) expressly preempts state requirements on labeling that are not the same as the federal requirements.
The states are also preempted from banning trans fat from ALL foods because that would interfere with interstate commerce. That is, a state cannot be the Crisco Cop and stop the shipment of trans fat into the state, when FDA has approved trans fat. In addition, a ban on trans fat from all food would be a direct conflict with federal law, which approves foods that contain trans fat. Basically, a state cannot stop the manufacturing, transportation, or distribution of foods containing trans fat.
In the case of New York City, however, the city was clever enough to claim that they are not regulating commerce, but only regulating food preparation at the point of consumption. This is an area that the FDCA never mentions. The NYC trans-fat ban may be preempted, but NYC has raised a colorable argument. In addition, the courts have traditionally been sympathetic to any law that protects the health or safety of the citizens—which, after all, is a traditional power left to the states. FDA authority to regulate food is based on the Commerce Clause, not the power to regulate food safety.
By the way, the National Restaurant Association (NRA) has threatened legal action to overturn trans fat bans, but so far nothing has come of it. The NRA probably don't want the bad publicity of being the identified as the supporter of killer fat. Here is NRA's site for trans fat legislation around the United States http://www.restaurant.org/government/state/nutrition/bills_trans_fat.cfm.