'Shame' is the most powerful tool to enforce social norms, BUT it only works if the majority is in on it.  This is so true.  I think that's why there are a few studies saying that fat people gain weight when they feel fat-shamed.  If you have one person telling you that you're a fat slob and 10 others telling you that you're beautiful and deserve another slice of entire pie, it doesn't take a genius to figure out which one they're going to believe. Compare to Japan where the entire culture is fat-shaming and lo and behold, very low obesity.