I think it's mostly bullshit if you generalize the experience of the author for everyone. Anecdotally however, I saw the same improvements to the letter when I

I think it's mostly bullshit if you generalize the experience of the author for everyone. Anecdotally however, I saw the same improvements to the letter when I stopped sugar intake (not just refined but stopped eating fruits, etc.). I can't remember any withdrawal symptoms though. It was rather easy, but then again I stopped because of diabetes scare.