well I have went on a 30 day and a 60 day juice fast.
I had gone on it as I had cancer (which has not recurred ut I did have some traditional treatments combined with a 150 supplements and some other alternative health treatments)
I was not thinking about my knee at all but I was doing a whole body hot and cold shower with it and also the incurables program so I cannot attribute it completely to fasting.
I had a torn meniscus cartilage when I was run over while walking by a women. They did not figure out my pain for several months and by then I felt the arthroscopic surgery they recommended would not be prudent as I had several risk factors.
It hurt every day and they said it would the rest of my life but this health building program took away and seemed to fix my knee although now many years later, I am getting Arthritis in it.
Another thing it helped me with was weight loss.
I always gained all my weight back plus more any time I lost weight (yoyo syndrome which I had noted many years before we started hearing about the yoyo syndrome.
I lost a lot of weight..the first time as I said I was also doing the incurables but the 2nd time--my 50 day juice fast, I was only doing that for the most part.
Both times I did not gain all the weight back even when returning to my normal high calorie (but mostly healthy) diet.
the first fast was almost 15 years ago and I only regained half of my lost 70 pounds. The next one about 2 years ago, I lost 60 pounds and then got injured 6 months later and still cannot hardy walk at all and must use a walker.
Even so, I yet again have only gained back 1/2 of my lost weight. these are the only two times in my life (now in my early 60s) that I have not regained all the weight I lost back plus more.
I feel it resets your body to a new lower set-point (i.e,-set-point theory of weight loss/gain)
After, the first couple days, all hunger mostly went away and I found it much easier than dieting as I was not hungry at all. Also noticed some clearer thinking and fantastic orgasms during this time.