Interesting. Personally, I can't see how that would be valuable in any sense, but maybe I'm just not understanding. I do come from a "eat unlimited portions of X category, limit Y category as much as possible, completely avoid Z category at all costs"-type of approach, so maybe that's why. It just seems to me that, defining what kinds of foods are bad for you and what kind of foods are not, and then letting your hunger control how much you eat, would be a lot easier/more sensible. If you're not eating garbage that screws with your blood sugar/hormones, then your natural satiety function should work well enough to make it difficult to consume more than you should.
Thanks for the explanation, though. This must be for the calorie counting/cardio crowd.