it is a matter of experience. i have learned about my body through self experimentation. i have had much guidance along the way. when i discovered MH, i found the answer to a few remaining questions and a lot of sustantiation of what i had learned so far. i would be hard pressed to improve on his school of self prevention. i have done nothing since discovering him here but learn or concur with what he says, and what i have learned, i have used and checked out. i have heard him say things that could be easily argued with using scientific data. the scientists are wrong.