During the 3rd or 4th day of fasting, hunger generally "falls away" and the desire for food starts to feel like a distant and irrelevant memory.

I honestly don’t know why this happens, but I figure it’s a cost-cutting measure — it takes energy to signal hunger, and after the 3rd day of getting no response to that signal, the body just figures it’s another process it can shut down to save energy.

It’s important, if you are doing a fast in which you want to keep your energy up and not lie in bed all day, that you keep taking in your Elixir anyway!  Lack of hunger is no excuse for passing out.