Hello brushie brushie,
you may be interested to learn that Herbert M Shelton encouraged the use of exercise for the purpose of weightloss during a fast, being careful not to overdo it. You will burn more calories that way.
You mention in your blog that you have a hunch that muscle will be lost first during a fast as opposed to fat, but in fact is the other way around..............
The body will conserve its most important tissue as a matter of priority, and expend its least vital tissue first. This is what Dr Joel Fuhrman refers to as "protein-sparing".
By the second and third day of a fast and thereafter, the body initiates a survival mechanism where the Brain, the heart, the muscles and the other vital organs begin to use ketones as a fuel source instead of glucose; so for example, by this time, and througout the remainder of the fast, muscle-wasting decreases to les than 0.2Kg per day. Muscle, like the other vital tissues/organs are conserved and where the max' breakdown of fatty tissue and removal of toxins will take place.
"that useless fat and the less essential tissues are consumed first, and the most essential tissues of the body are hardly touched, even where death from starvation results.
"Diseased" tissues are broken down, exudates, effusions and deposits are absorbed and either used or eliminated. The body utilizes everything it can dispense with during a fast in order to preserve the integrity of the essential tissues. The useless and least essential things are sacrificed first"........................... http://www.soilandhealth.org/02/0201hyglibcat/020127shelton.III/020127.ch4.htm