Obesity isn't really a sign of making a good living. As odd as it sounds, it costs more to have a diet that helps you stay thin, then one that helps you become ...well, not thin. Carbs, fats, and sugars are relatively cheap, easy to put into processed food, make you feel full, and taste oh so good. Fresh fruits and veggies tend to be more expensive. At our local supermarket, I can buy three or four large oranges for about the same price as five pounds of starchy potatoes or who knows how many packs of ramen noodles (which I hate to say is not really what you want you family to be subsisting on). Beans and lentils are cheap and good nutrition, but take more time to prepare.

Fast food/junk food seems cheap, tastes good, feels good but can pack on the pounds.

Excuse me, I've gotten hungry writing this.