There are gradations of fasting measures ranging from rigorous to relatively casual. Water fasting is the most rapid and effective one. Other methods have been created by grasping the underlying truth of fasting, namely whenever the digestive effort can be reduced, by whatever degree, whenever the formation of the toxins of misdigestion can be reduced or prevented, to that extent the body can divert energy to the healing process. Thus comes about assorted famous and sometimes notorious monodiet semi-fasts like the grape cure where the faster eats only grapes for a month or so, or the lemon cure, where the juice of one or more lemons is added to water and nothing else is consumed for weeks on end. Here I should also mention the "lemon juice/cayenne pepper/maple syrup cure," the various green drink cures using spirulina, chlorella, barley green or wheat grass, and the famous Bieler broths--vegetable soups made of overcooked green beans or zucchini. I do not believe that monodiets work because of some magical property of a particular food used. They work because they are semi-fasts and may be extremely useful, especially for those individuals who can not or will not tolerate a water fast. The best foods for monodiet fasting are the easiest ones digest: juices of raw fruits and nonstarchy vegetables with all solids strained out. Strained mineral broths made of long-simmered non-starchy vegetables (the best of them made of leafy green vegetables) fall in the same category. So if you are highly partial to the flavor of grapes or lemons or cayenne and (highly diluted) maple syrup, a long fast on one of these would do you a world of good, just not quite as much good as the same amount of time spent on water alone. If you select something more "solid" for a long monodiet fast, like pureed zucchini, it is essential that you not overeat. Dr. Bieler gave his fasting patients only one pint of zucchini soup three or four times a day. The way to evaluate how much to eat is by how much weight you are losing. When fasting, you must lose weight! And the faster the better.