When we go out to eat as a family, which is usually about once a week, we would let the kids (now 14 and 11) order a soda, which was the only time they drank soda because we don't keep it at home. I never really liked the idea because I think soda isn't healthy, but my wife had a point that making something off limits can make it an object of intense desire.
One day, in a flash, this occurred to me. I told the kids that when we go out, they can order a soda, or drink water and I'll give them $2. They almost always take the $2, and they really like it. Not only are they not consuming all that sugar, they are learning the economic concept of opportunity cost. In this case, if they don't drink a soda, they can do something else with the money.