Forgive me if this has already been addressed in one of our Stephan threads. I'm not sure that it has, because it's kind of like a background question for the main issue.
I have an intuitive understanding for why various changes to our way of living can lead to a lower body-fat setpoint. (Note -- I am assuming the setpoint theory, at least for the time being, and so rejecting that calories in and out can give a full explanation of what's going on. Relevant Paleohacks threads here and here.) So, for example, if you do a lot of sprinting, then you're telling your body "Hey, I need to sprint" and your body responds with "OK, I'll give you the kind of body that can sprint -- a leaner one." Sprints can lower the setpoint. I have an intuitive understanding for "metabolic repair" as well. If you screw up your body with fructose and PUFAs then some kind of mechanism goes out of whack (please have mercy on my simplification!) and if we repair that mechanism then we lose body fat, and for good. We bring our body back to the shape that nature intended. Fixing your metabolism can lower the setpoint.
But what kind of intuitive explanation can we come up with for the food reward theory? I just don't see why eating more delicious food would incline my body to carry more fat. Or, put inversely, I don't see why eating less delicious food would incline my body to carry less fat. (Again, warning, we're assuming that it's not just so simple as: delicious food causes me to eat more of it. Because if the theory is right you could be cruising along at a stable body weight, eating delicious food, and then start eating plainer food and then find a new, stable, body weight.)
Does this make sense, what I'm trying to get at? Does anyone have a plausible backstory for plainer food leading to a lower setpoint? Perhaps Stephan himself addresses this somewhere on the blog? Thanks, P.