Well, the poor tend to be, generally, less educated. It's not a far stretch to assume their schooling in nutrition and health is just as poor as they are financially, if non-existent. They just see "food". Honestly, I've seen people try and argue that fish 'n chips are a healthy, balanced meal. Some people will look at you, right in the eyes, and unflinchingly (and with the whole of their belief) tell you that a carton of french fries is good for you, because it's multiple servings' worth of vegetables; especially if it's fried in vegetable oil. That and sheer laziness make for a pretty crappy bill of health. EDIT: this is meant to be more of an observation on the state of people's health, based on the quality of the food they eat. Of course, if you're fat, you're eating way too much— whether that be shit food or not.