> just like brushing your teeth leads to better health outcomes

This is very context dependent. If you grow up surrounded by a typical western/industrial/post-industrial diet, then yes, it almost certainly does.

But you could also change the food environment.

Hopefully the analogy/metaphor that connects this to schooling is reasonably obvious.

So... We need to go back to living in the jungle?

You go do that then. Enjoy your slow death from malaria.