There is some unusual advice given by the Rambam regarding health. He says that there is a general rule regarding a healthy body: Any time a person works out in the form of exercise to the point that he is יגע, weary from the activity, no sickness will come to him.
He also adds in הלכות דעות that he guarantees that one will never be sick if he eats right. Good eating includes the proper quantities of winter fruit and summer fruit. One must keep his body in a state that he's able to easily eliminate waste. This is done by maintaining soft stools. This is the key to preventing illness so that the body is fine tuned and functions at the highest level.
I don't recall reading anyone but the Rambam who bothers to give specific advice in health issues. He says that when the Torah says, והלכת בדרכיו, to walk in Hashem's ways, we are to walk and not crawl.