How about educating parents, teachers and school administrators? If we're looking for change, it has to come from a good place (forced won't work). We need our educators (yes, parents are educators too) to embrace the cause and become more than just a moving piece.
If we can get these people to change the way they think about food and then actually live the difference, we'd be making HUGE strides. From there, it's a question of allowing children to follow in their footsteps.
Kids, especially at a younger age, love to copy people they admire and believe it or not, they admire their parents and teachers although they don't always show it.