<<Disclaimer:  Verify this information before applying it to your situation.>>

Hey - my name is Kristine, and I'm 18.  I don't know if I can be helpful
with this, cuz I never really had much of a desire to eat junk food. I've
never had a Coke, pretzels, etc.  I guess for me, that food didn't have
much of an appeal. It seemed fake, artificial, like "junk" food. I always
liked the food I ate.  I think the main thing, and the parents need to
start this when the child is young, is not to make that food desirable to
the kid.  Make his/her food seem yummy and special. It helps if the
parents try not to eat junk food (at least around the child) My parents
(primarily my mom) is very health conscious - even my bro, who isn't
celiac, never really ate junk food - at least not at home.  It's the
parents responsibility to make sure the child doesn't feel he/she is
missing out.
Kristine