No, the Science
behind juice fasting is similiar to water fasting. In both ventures your body slips into a state of autolysis, a natural state of repair where digestion stops, which is why people don't die from fasting but will quickly die from starvation. Look into books like, "The Juice Fasting Bible" or "How to keep Slim, Healthy and Young through Juice Fasting". Both were written by MDs.