[Benjammer]

That's because personal health & fitness is treated as a completely personal endevour in society, much like most of what we call "parenting," at least in most parts of the US. You could design the perfect curriculum based around teaching holistic personal health habits at specific age-appropriate levels, but the first time the fat kid goes home and says "hey maybe we shouldn't have mac N cheese or casserole for the 4th night this week" you get the fat parents making a fuss over their kid making them feel bad or just for questioning them at all.

"School" is a product that must be sold to the parents, the people "signing the checks" with their local tax money. It's kinda like enterprise software. The users are not the people making purchasing decisions, so you're always going to end up with a bad incentive structure for the quality of life of end-users (students) if the decision-makers aren't fully aligned with the users. How many fat parents are going to be on board with the school teaching their fat child a healthier lifestyle?

Right now, it appears that parents want a product that gives them the _feeling_ of caring about their child's long-term health habits, without them personally needing to make any changes to their lifestyle or parenting style.