Which, ifyou will pardon me, is the whole damned point. It takes time and effort and work and study to learn one's body, and again, as a 68 yo athlete and lifetime body builder who has done some genuinely stupid shit to my body, this is the ONLY way to get and stay healthy. Our bodies change over the decades, and there is no one thing that will work forever other than to pay attention. Watch what works, watch what doesn't. And, kindly, STOP doing shit that doesn't work or damages us. Why on earth is this so bloody hard?