It is true that one who is steeped in the world of Torah generally does not suffer corruption of character, but that is not the primary purpose of the mitzvot.
On the other hand, the Torah would never command us to do something that clearly damages or destroys the body.
The Midrash states, “Nothing that is evil descends from above” (Genesis Rabba).
In other words, no mitzvah would be given that causes damage, whether physically or spiritually.
That said, it is still quite a stretch to then pin everything on this point and search for each mitzva’s physical and personal benefit.
God did not descend on Mount Sinai to provide information that can be found in a cheap psychology textbook – to explain how to improve one’s life and how to behave better.
–Rabbi Adin Steinsaltz