My 8th grade english teacher once talked about the topic. A few years back he and a few other teachers went about creating a "healthy lunch" plan, which would rid of soda, extravagantly sweet stuff, and replace it with their healthy counterparts (or something like that). He took the plan up to some specialist people in the administration for evaluation, and they said "NO".
The reason is, because the school needs money to function. Apparently soda profits are an integral part of a school's funds. Sure, the school may value students' health, but to improve on that would mean a decrease in funds, which means an inferior learning environment (although I'm puzzled what the administration people meant, did they think that students wouldn't eat/drink the healthy stuff? (that would decrease funds) Or does soda get more profit?). An unfortunate conclusion.