I wonder, though, if you can ever develop the ability to USE stored body fat (as a healthy human is generally able to do) if you keep your body in a constant mode of digestion.
You couldn't pay me any amount of money to keep my body in a constant mode of digestion -- it seems like your body is always working, whether it's pushing food through the stomach, or breaking it down further in the small or large intestines -- and how can you ever have a moment of relaxation in your entire life if you are always making your body work so hard???
In addition to having a body working away in a constant state of digestion, there is the additional matter of how hard the cardiovascular system has to work if the body is carrying around stores of excess body fat. So, it just seems like life becomes harder than it has to be, if we overburden the organs of digestion as well as the organs of circulation.
When I, in my own life, experience feelings where my last meal is almost fully digested, and it will be time for a meal soon -- I remain pretty happy and functional. I don't find that I have to run to the nearest bowl of lentils or hunt down a pear really fast. It just feels natural.
So when people are experiencing something very, very different from that, I wonder whether it's more like a physical and/or emotional withdrawal process (like when a smoker cuts back on his cigarettes) that's rearing its head. It strikes me that a person who is eating healthier or eating less, sometimes feels such a level of distress to have their familiar patterns and their comfortable coping mechanisms not readily at hand, that a certain amount of stress hormones enter the system, and disrupt their feelngs of well-being.
Well, that is just an idea. If you don't like it, then you may of course feel free to disregard that! But that is how I see things.