Sparkpeople does not approve or endorse the use of a "juicing diet". It is not an appropriate weight loss technique. It would not provide the nutrients your body needs, it would probably be too low in calories; and it does not help you learn behavoirs to achieve and maintain weight loss.
A juice diet used for a short time period will probably not be dangerous to a healthy adult, but it would not be considered a healthy weight loss technique either.
SP Dietitian Becky