Whatever some people may say--I just know that both of my maternal grandparents followed this book for some 50 years and both lived very long and healthy lives. My grandfather died when he was 93 and my grandmother who just turned 90 is currently traveling in Europe and stands on her head once a day for improved blood circulation. Fasting is not easy but as they say: "no pain no gain." Also, the book goes well with a yoga exercise routine. I am currently looking to buy this book for a friend. Five stars.