I saw the documentary where this "reboot" idea comes from. It's called "Fat, Sick, and Nearly Dead."
It's really fascinating-- I definitely recommend it. You can watch it for free if you have Netflix streaming.
In the docu, this Australian guy went for something like 2 months just juicing and literally transformed himself, inside and out. His juices were *mostly* vegetables with a little bit of fruit. I think that "Mean Grean" one is the main one he drank.
He healed a skin disease he'd been suffering from for years, dropped loads of weight, and lots of other good "internal" things. Then he helps some other people do some detoxes along the way.
Oh, and on a shallow note, he goes from looking paunchy and middle-aged to really cute!!
There's nothing unhealthy about it, and so I say go for it if you can stick with it!