I think there's a very delicate balance when it comes to how food/nutrition/weight is handled with children. If it becomes a huge issue or battle, there will be problems. Isn't this how bulimia, anorexia and obesity can get started? A fixation on food and weight, hoarding, 'good food' and 'bad food', "food is love", etc. I try to be pretty casual and matter-of-fact with my kids re: food. There's food that is healthy for you and food that is not so healthy. It's okay to have not-so-healthy food occasionally, but also to eat when you're hungry and stop when you're full.

Also, sometimes the money teens are spending on junk food is from jobs (ie paper route, babysitting) or friends' parents are giving them 'treats' at their house. Also, if you're child takes lunch money to school (I'm talking high school), how do you monitor what they buy?? I think, as with so many things as a parent, you need to trust that you've taught them well and let them have some room. There's no use trying to police them constantly (on food and many other things), or you'll drive yourself (and them) crazy. Trust the job that you've done