When I am doing Sidha Samadhi Yoga 1990 (SSY) I use perform fasting continuously 5 days, I don’t know that days but when ever I do Advance Mediation course (AMC) I use to fasting 3 days and final day I break that fasting with raw food and fruits. That experience is amazing and energetic and keeping me in awareness.
Recently I saw this video in youtube from Dr.Eric and I amazed technical specific and details what will happen in side our body in fasting. It was really fantastic. I was done 3 days again before shivratri. At least once in a month I should perform fasting.