above you wrote again that Shelton advocated bed rest, because "people who had come to him as patients in varying degrees of ill-health and disease". But surely in the Russian fasting clinics of the 1960-80s, they did not fast healthy people, but precisely those chronic patients who could not be helped with conventional methods. Those were the people who had tried everything and came to fasting as the last resort. Russians absolutely forbade bed rest for their fasters -- and there are many physiological reasons why and how physical activity facilitates a fast.
When I said above that I agreed that bed rest was appropriate for the very sick, I had in mind either a severe injury (like falling out of a window lol) or being hit by a bug like mononucleosis, when the weakness is such that even the smallest movement requires a great mental effort. Barring this, every faster must at least go for a walk, at least 10 km a day, as Russians required from their fasters.
That healthy people pump iron and run miles during their fasts is a given. Moderate physical activity --and absolute prohibition of bed rest-- is what those who turn to fasting to improve their health should do.
Bed rest is counterproductive during a fast and Shelton was very wrong to insist on it. Again, his lack of personal experience was his major flaw. If only he fasted himself he would have known this.