Pure absolute water fasting while not taking any vitamins or other nutritional supplementation has a very limited maximum duration, perhaps 45 days. The key concept here is nutritional reserves. Body fat is stored, surplus energy fuel. But energy alone cannot keep a body going. It needs much more than fuel to rebuild and repair and maintain its systems. So the body in its wisdom also stores up vitamins and minerals and other essential substances in and in-between all its cells. Bodies that have been very well nourished for a long time have very large reserves; poorly nourished ones may have very little set aside for a rainy day. And it is almost a truism that a sick person has, for quite some time, been a poorly nourished one. With low nutritional reserves. This fact alone can make it difficult for a sick person to water fast for enough time to completely heal their damaged organs and other systems. Obese people have fat reserves sufficient to provide energy for long periods, but rarely can any body, no matter how complete its nutrition was for years previously, contain sufficient nutritional reserves to support a water fast of over six weeks. To water fast the very obese down to normal weight can take months but to make this possible, rather diverse and concentrated nutrition containing few calories must be given. It is possible to fast even a very slim a person for quite a bit longer than a month when their body is receiving easily assimilable vitamins and minerals and small amounts of sugars or other simple carbohydrates. I estimate that fasting on raw juices and mineral broths will result in healing at 25 to 75 percent of the efficiency of water fasting, depending on the amount of nutrition taken and the amount the juices or broths are diluted. But juice fasting can permit healing to go on several times longer than water might. Fasting on dilute juice and broth can also save the life of someone whose organs of elimination are insufficiently strong to withstand the work load created by water fasting. In this sense, juices can be regarded as similar to the moderators in a nuclear reactor, slowing the process down so it won't destroy the container. On a fast of undiluted juice, the healing power drops considerably, but a person on this regimen, if not sick, is usually capable of working.