And this is why I voted for you in the 2011 best user tournament!

The cheapest food in the US also happens to be some of the most unhealthy food. Fast food, junk food, soda, candy, it's all very cheap & seems to provide the most calorie bang for the buck. The major government farm subsidies go towards growing corn, which ends up making corn syrup, corn chips, and other corn crap. Companies love making highly processed foods which can last on shelves for years without going bad, it helps the bottom line if the food doesn't go bad. If our govt actually cared about the population, more subsidies would go towards growing leafy green vegetables & fruits. If our govt actually cared about helping poor populations, they would subsidize farmers markets and vegetable stands in poor communities. Areas of low income are commonly known as "nutritional deserts", where it can be nearly impossible to even find a vegetable. There's also a total lack of nutritional education in our schools. The funny thing is, if the govt actually improved on these areas, it would probably save our country billions of dollars in unnecessary healthcare costs, which mainly deal with diseases and problems arising from people eating horribly.

It has more to do with easy than cheap.

Second that.

Typically, the cheapest items in my grocery basket happen to be the least processed, highest rated in micronutrients. Fruits, vegetables, frozen or fresh; doesn't matter what's in season, brown rice, whole wheat, black beans, eggs, mushrooms, potatoes, etc. About the only expensive minimally processed foods are foods like quinoa, salmon, organic honey. 

Key thing to note here is that all of those things are ingredients (barring fruit) that have to be prepped or cooked. Not surprisingly, the no cook, no prep snack/junk foods tend to be eaten first. They also tend to be higher in macronutrients and lower in micronutrients. In other words, foods that I don't need to eat, even just for the calories, since about the last word I'd use to describe myself is starving.

If money is legitimately a factor, then it would behoove the non-wealthy, non-caviar and fois gras eating common folk to follow a health blog or two and learn how to prep food and cook. People have been doing it for millenia; it isn't hard.

Dollar for dollar, you get more CALORIE bang for your buck in the snack aisle, than in the produce section. Sorry to say, but that's a very simple fact. Yes, brown rice, eggs, and some other healthy things are relatively cheap, no doubt. But dollar for dollar, processed foods and meats provide far more calories, although they are much less healthy calories.

Diet diet diet diet diet.

Speaking as a "minority" that is what its all about. Don't let Mississippi's gross statistics fool you.

That might be an explanation for a malnutrition problem (if people were taking in an adequate number of calories by eating junk food but lacking the nutrients they needed to be healthy) but that is obviously not the problem we’re facing in the western world. If you can afford to eat an excessive number of calories in junk food you can easily afford to eat an appropriate number of calories in healthy food.

Being that there is a demonstratable relationship between greater obesity in countries where people spend a lower percentage of their take home income on food, I don't think you can arge that people are eating poorly because they can't afford to eat better. After all, if people can be skinny while spending 13.5% of income on food why are Americans fat while only spending 6.9% of income on food  ( http://civileats.com/2011/03/29/mapping-global-food-spending-infographic/ )?

The reason why poor people are more likely to be obese is the same reason why poor people are far more likely to smoke; and I don't think anyone is dishonest enough to argue that smoking is less expensive than not smoking.

In a nation where the majority of the population is considered overweight (but not obese), macronutrients or simple raw caloric intake is not the issue. About the only percentage of the population that has to worry about that would be those who don't have access to inexpensive food, processed or otherwise due to isolation (living in the mountains in winter or in the middle of a desert) and that is definitely NOT the percentage of the population in question here. 

Of course a pound of peanut butter or margerine has more calories than a pound of apples or celery. It also has more calories than a pound of cheeseburgers, pizza or french fries. Anyone who isn't losing weight at unnatural rates due to malnourishment doesn't need to worry about getting "more calorie bang for their buck" by eating processed, pre-packaged snack foods. People who do will encounter the ill health effects of malnourishment due to the lack of micronutrients long before they ever experience any signs of starvation.