States and municipalities across the countryfrom New York City to the State of Californiahave banned partially hydrogenated cooking oils, also known as trans fats, in restaurants under their jurisdiction. This much is apparent: Trans fats are bad for you. But government regulation is bad for you, too. Seemingly innocuous and well-meaning interventions can lead to less innocuous, less benign interventions later. Should we trust the state to regulate what we do, even when it is for our own good? Further, if were going to regulate, why should we stop at trans fats?