Rebooting your system is a big one. Think about it, how often do you crave a cheeseburger rather than a salad? Because we eat so many processed foods, our brain starts needing it. The brain forgets what is good for it, and starts telling us we need some fries and pizza.
By going on a vegetable and fruit only juice diet, we're rewiring our system to enjoy the things it should. The best part is that these juices taste great, and will make you want a salad more than you ever did. It's literally a system reboot.