I agree with you on the teachers being able to pick the ones in trouble - or at least they should be.
My daughter is a little bit of nothing......but she is actually both taller and heavier than I was at her age. I'm not worried about her in the least. She'll be 8 in July, I was 13 before my height really started showing and my husband grew more than an inch AFTER he was OUT of high school.
As to the vegghie bowls, I only mentioned the celery and carrots because they can be had all year round and I don't bother growing them (too much work).
I keep junk food snacks around here, and won't deny them to my child or her friends when they ask for them, because more times than not they will raid the veggie bin in the fridge before they head for chips or cookies. There has been more than once that I reach into the bin to pull out stuff to make a salad and basically find a head of lettuce in there, the kids have eaten me out of all other fresh veggies :)
Tuesday my daughter and her friend are going to really learn just what it means to want somethings in the garden. They both want watermelons and pumpkins (neither really interest me) and so after they do their homework they will be out in the field getting rid of the weeds and preparing the area to plant those seeds on Thursday.
I've got 10,000 sqaure feet tilled up and can till up more - but these girls are going to learn that if they want it planted and harvested and it is not on my plans for my goals, they are going to have to deal with it themselves.
I'm a hard taskmaster - but I'm a lot better than the Nanny State so many wish to put these girls into. If nothing else, they will both learn self sufficiency at an early age.
It's great that you are going to teach your daughter and friends to grow their own treats. I'm not big on gardening stuff (I hate worms!) but I love heirloom tomatoes and loathe supermarket ones. So I have to make some compromises. :-)
Why not just give the kids vegs instead of junk food? They like the vegs, and I have to say that I am happy that I never developed a taste for sugary things. Weight control is easier if you don't like cookies or donuts.