Your idea of dry fasting is based on religion and has absolutely no scientific basis to it. My knowledge comes purely from the Science of dry fasting which has been at a large degree developed in Russia since 1990. The had medical facilities testing patients and analyzing the processes the body goes through as a person fast. The final healing crisis occurs between 9th and 11th day and without going through it the root of the disorder remains within organism, which gives a high chance for the problem to reoccur.
Also your statement that, "We are given pain and illness to cure us of our sins and to prepare us for a higher level in this life and in the hereafter." is absolutely preposterous to say the list. I am 42 years old, I have four children and I've got my large share of sins in the past, yet I am also absolutely healthy. At my age when so many women suffer from chronic diseases I have nothing to report. In fact the only problem I've ever had was human papilloma virus several years ago, which disappeared on its own. So based on your statement I must be a saint, however, I would never claim that.