There are no bad foods, only bad diets. Why pick on sugary drinks, but leave ice cream shops alone. Why not put a hazard tax on buffet restaurants. Imagine the government decides they don't like the way you live your life, so they make laws to screw you and people like you. Laws are the worst way to attempt to improve human dietary behavior.
You could advertise fitness, create tastier low calorie beverages, even advertise drinking a full glass of water before eating. Positive fitness outcomes can be found using non punitive means.