Worked until it didn't
I watched the movie last year and did the juice fast for 30 days. I dropped about 20 pounds in a month and probably would have done better but I tended to have more fruit juices than veggies.
It all came back over about a six month period, because I hadn't changed anything about my diet.
Now I'm on a Paleo diet with no wheat, no grains, no dairy, no sugar and I'm back down 20 pounds in a month. Light exercise including squats, pushups, pullups, planks, and stationary bike for an hour 3x a week. Once a week I do sprints on the stationary bike for some high intensity training.
The juice fast is okay for a kickstart, but you need to have something you can live with. Good luck!