I've tried fasting and I can only confirm its benefits. For a period of a year I fasted one day a week when I would only drink about three liters of water and I really felt more clean inside and more in touch with everything spiritually. Regarding Osho and his self made cult I have mixed opinions and most of them are not of praise thus I will recommend you to watch also another documentary on youtube about the Rajneeshes:

In terms of spiritual wisdom and spiritual teachers I always recommend Nisargadatta Maharaj's books which for me are life changing. A true guru in my opinion.