Interesting information, I didn't know about the role of leptin. What I am concerned about is the fact that sudden or extreme fasting results in hormonal imbalances and metabolic syndrome. When deprived of food, our bodies feel threatened and try to survive by slowing down metabolism in order to be able to store all available food. This decreases cortisol binding proteins which increases serum cortisol and in turn contributes to insulin resistance and metabolic syndrome. A way for the body to retain food is by producing more of the rT3 hormone, which is essentially the "reverse" of thyroid hormone T3.

Apart from the fact that one will be gaining weight much easier in the future due to the metabolic syndrome, excess rT3 will block the regular T3 receptors and prevent its absorption in the body, causing thyroid issues as well.

So although I don't disagree with the fact that fasting reduces inflammatory pain, I would advice practitioners to be cautious and take their time for the body to adjust.