The evidence that the poor are forced into buying potato chips rather than apples by their incomes is pretty underwhelming. As Mixner says, the food is cheaper per calorie, but that's the point--they buy things that have a lot of calories, when there are at least equally cheap foods available per serving that have fewer calories. You may have to buy chicken wings instead of breasts, but you don't have to bread and deep fry them.
Sure. Junk food is omnipresent in America, whereas fruit and vegetables are much harder to come by, but it's really poor people's fault that they're fat. After all, they deep fry everything they get their greasy, outstretched paws upon! They're fat because they make bad decisions, and they make bad decisions because they're stupid. And we know they're stupid because they're poor!
I'm not sure if this is better or worse than this example of compassionate conservatism. I suppose they're equally stupid and disgusting.