Susan Guest hasn't eaten in over three days. And she says she has never felt better.Why? Because she and lots of other women are now sipping juice at least three times a day. It's part of a program called "juice fasting" and these women say they stop eating food and they have never had so much energy. The new age health spa in Neversink, New York, which has a group fasting program says its fasting clientele has doubled in the last two years. Clients fast for three days with fresh fruit and vegetable juice and potassium supplements ... All in the name of detoxifying and cleansing the body and quickly shedding a few pounds. A lot of people have sugar addiction, caffeine junk food, they want to use the fast as a transition to better eating. Other benefits to this programs include clearer skin, mental clarity, increased energy and weight loss. Dr. Louis Aronne, Director of the New York Presbyterian Hospital's weight control program says juice fasting for less than a week is probably safe but not particularly useful. She says the juice fast will provide an inadequate number of calories, which can be inadequate. Fasters say the first and second day are usually rough, with hunger pangs and low energy. But they had a rush of energy on the third and fourth day. Fasting proponents say that's a sign your body is healing -- but doctors say there's no credible medical evidence that your body is in fact healing.