The brain’s job is to take care of the body and the body helps the brain to do that. This story talks about how what someone eats and how much they sleep and move around helps them to keep their body and their brain healthy.
Being “physical” means you move your body. Any kind of moving around is good for your body and your brain.
You eat because food gives your body and your brain the energy they need to make us healthy.
You sleep because your body needs to rest and your brain has lots of other things to do to make sure that we are healthy.