Kids learn at different speeds so a good education system takes that into regard. Systems should be transient that slow starters can catch up at a later time and reach higher forms of education.

We need more teachers and smaller groups. Eating healthy can be a course, but you quickly loose all the pupils that already learned that from their parents.

Mental health is hard to teach and there is little certain knowledge here, it only works individually. Aside from really hard cases, I think children have quite resilient minds.

I believe the reluctance to do physical exercise has other sources, not really lacking education. But PE is vastly to be preferred to medicating "unusual" behavior.