lemon juice cleans your system out.
Try drinking grapefruit juice once a day for two weeks and see what happens.

No.
Eating less calories then you burn causes weight loss.
"Triggers' for your metabolism have a fairly minor impact.
Overall muscle level, activity level and - most importanltly - what you eat will drive weight loss.

This is what i found.
http://www.faddiet.com/diettipnum11.html
I think a small portion of everything is ok, overdose of any particular fruit juice is not really good for some other consumers.