We intuitively balance our freedom with reasonable regulations so that we can live together peacefully. Banning smoking in public places to protect others and banning large servings to protect people from themselves are different. That's why the first is popular (at least now) and the second ridiculed. It is the same reason that people have guns at home but not in banks or people can say what they want, but not always in court. Time, place and manner restrictions are accepted even on constitutionally protected rights because they make sense to most people agree. The Big Gulp law goes too far and does not have a reason people see for the restriction.