Juice diets are horrible.  I have a juicer at home for the rare occasions when I want to drink fresh juice.  8oz of orange juice has about 4 whole oranges in it...about 120 calories.  Why not just eat fresh fruit?  It is much more filling and has a third as many calories.  The problem with juice is that it is too easy to drink too many calories...I often see people drinking 20oz of juice at a time...which is almost as bad as eating a candy bar...