No one who has any sense of free thought would depend on a book, a doctor, an "expert". Gather all your data. If it isn't dangerous, experiment with it prudently. Sometimes you need to tweak things a bit here & there, but see if it makes any difference. Do your own detective work as no one can do it for you...they don't live in your body.
First and foremost, basic dietary and lifestyle regiment MUST be changed to support health or NOTHING will work long term.