I know you said that was just a theory, but it's a variation on a too-common theme that I - and many others - find offensive. The experiment specifically involved people who have the same current socioeconomic status. Some had been affluent all their lives, while others had become affluent from poorer beginnings. If self-discipline is what allows some to become richer than others, don't you think those who became wealthy by their own efforts might know a bit more about it than those who had their wealth handed to them? Why, then, would they still exhibit this distinct reaction to offers of food? I don't think your theory has any explanatory power at all.