the biological and or physiological effects of fasting are well known. There is no mystery as to what occurs on a water-only fast.
For example, it is well-documented that the body transfers from the burning of glucose to that of ketones in order to provide an energy source for the body, and where the process of autolysis is very selective in the materials it uses for this energy-source by ridding the body of its effluent materials first and foremost, whilst leaving the essential tissues until last, and the starvation period has begun in earnest.
Even in death from starvation, it has been shown in Yeos and Chossats physiology, that the essential organs and tissues are well-preserved, and suffer few losses compared to the fats and subcutaneous/adipose tissues which have become exhausted.
I think you will also find that fasting is extremely beneficial for anyone that utilizes it, and any unsuccessful attempts are usually attributable to the "conduct" of the fast, rather than the fast itself.
Contraindications to fasting are few and far between.
Double-blind and/or open trials only apply within the realm of drug-trials against disease, as each individual who undertakes a fast is unique, and at a very different stage and development of their disease/health status. Fasting works on the basis of "Evidence-based medicine" and not "Science-based medicine".
The proof of the benefits in fasting lie within the annals of fasting literature dating back to the early 1800's to today, and from the thousands upon thousands of individuals who have recovered their health when Mainstream have largely failed them previously.
Your comment that there is: "no proof that the toxins we consumed as a child and adult stay there permanently, or that fasting removes them all",..............we should bear in mind that the body is constantly in the processes of catabolism and anabolism or the breaking down and building-up of tissues in metabolism, and where fasting creates an acceleration of these processes.
Toxins (any substance that is recognized as foreign to the body) and which includes pesticides, preservatives
and so on, are mainly, but not exclusively, contained with adipose and subcutaneous fat deposits, and in the process of ketosis and autolysis are broken down and released into the bloodstream where they are then expelled by the organs of elimination.
It is true to say however that one long fast may not be sufficient time for the complete elimination of these toxins to take place, and where a subsequent fast may be necessary to achieve this.
This has been the experience of qualified Natural Hygienic Doctors over the last century and a half.
Test results are not required, but sufficient "results" have been obtained in the analysis of urine to establish this.
There are no definitive tests to prove one way or the other that distilled water is harmful in any way, except to say that most people (the vast majority) who have fasted with this water, have had no ill-effects but only distinct benefit (as in my own case).
If you are looking for definitive proof then you will be hard-pressed to find any except the voluminous testimonials that exist where distilled water has been used.
We should also bear in mind that the rain cycle produces distilled water in Nature, and it is only the intervention and influence of man that perverts this quality via atmospheric pollution.
With regard to "Science"; the Science
of today has largely changed from the Science
of yesterday, and where tomorrows Science
will be as different again.
Science is ever-evolving. The theory of evolution for example is just that: a theory. Evolution cannot be measured or observed which is the yardstick for proof, but taken as fact by many scientists and taught in schools as such.
I agree with you: "knowledge of actual facts (not hearsay) is the key to good health".
Examine the "factual testimonials" from the time of Hippocrates and Paracelsus concerning fasting, and you will understand what this means.