Where is the clause in the Constitution that says Congress shall protect us from what we eat?
These morons have got to go!
Although I'm not sure this is a good idea (I think food labeling is an important and useful tool, but I'm skeptical of imposing the costs of reprinting signage/menus/etc in what is already a fairly bleak economic situation for the restaurant industry), I don't there is any Constitutional problem with this law. Limited, as it is, to large chain restaurants (which have stores in multiple states), this law appears to be a fairly clear exercise of the Federal power to regulate interstate commerce (and not even just under the current, strained, post-
Wickard reasoning, but under a reasonable reading of the plain language of the interstate commerce clause).
It might not be a wise exercise of Federal power, but it is not an unconstitutional exercise of Federal power.