It can be a less demanding option than a water fast, due to the fact that ingesting 2/3 liters of green smoothies and juices, with very high amounts of nutrients and fiber, makes it totally imposible to feel any hunger pangs. He differnce between juices and smoothies is precisely thatthe latter keeps all its fibers and thereby is more filling.
I personally like to alternate between both, depending of how I feel. I have persoanlly been through the experience of 3 prolonged Juice festas (30, 40 and 50 days), which gave the possibility to experiment first hand its benefits as well as the challenges it might entail. I have described those experiences in my blog (in spanish only), and was so enthusiastic as to the changes it brought in my life, that I decided to study more in detail the whole process through a Certified Juice Guru course.
It will be a pleasure to teach you how to prepare those delicious drinks and to explain how to very easily integrate them in your daily life, once back, without any major effort. This can literaly be a life changing practice.