My mum used to fast every year. It was always hilarious watching her face as she was trying to drink a big glass of sauerkraut juice and other terrible fluids. There is a photo from each year of this event. I recently tried the fasting myself and its not totally easy. After a few days of strange juices and teas you feel slightly lightheaded and strangely excited about vegetable stock. You are also prune to arguments about how many deciliters of potato water you are allowed in the morning. As potato water is a raw sliced up potato soaked in cold water that you drink the next day, discarding the potato and adding a teaspoon of lemon juice, the argument is normally revolving how FEW rather than many deciliters you have to drink.