Your muscle mass might suffer a little bit, but nothing too dramatic. It definitely won't be like me: I had my bow pull set as high as it could go two weeks before my gastric bypass, and then four months later I couldn't budge it.
I've done three or four liquid diets - clear and full. At first I feel fine, but by day five or six of protein (+ gatorade for carbs) land I feel pretty blah. It's going to be interesting to read about your experiences with juice and quackery.
I really hope it does work out, but a word of caution: make sure you read up on everything that can go wrong with this detox and watch for the symptoms. Other than that, good luck and have fun!