You will not gain weight or turn orange if you are drinking just a glass or two a day. Fruit juices should be made as an occasional treat, as they are a concentrated source of natural sugar. Strive toward developing a taste for vegetable juices. Canned or bottled juice is dead juice. As far as I know there is no enzyme activity and pasteurization has destroyed most if not all the vitamins in canned and bottled juice.
Live nutrients begin to die as soon as the juice is prepared.
I call it the Power Boost Drink this at least 15-30 minutes before eating solid food. A great article on juicing.