The Smoothie Diet program is based on roughly 1600-2000 calories per day. For about 3 weeks you will be replacing a meal per day with a smoothie. The smoothie mix is designed to be a meal replacement and will provide about 400 calories each. Your other food meals should aim at being around 500 calories each for best results.
Note: Even though this program is for 21 days, you can continue using it for as along as you want to lose as much weight as you want.
There are less chances of “rebounding” as this plan is not an intense diet plan meant to have quick temporary results.