It's no secret that human beings need energy, and juicing gives us exactly that. By drinking the juice from fruits and vegetables rather than eating them, we're outsourcing our digestion, and spending much less energy digesting our food. Look at all the fruits and veggies it takes to make just one glass of juice, all these good things are going straight into your system and being efficiently transformed into energy.
This also translates into weight loss. You're eating much less, but because you're getting all the energy and nutrients you need from the juice, you feel much more full. It's small portions, with big nutritional benefits, so start juicing.