Ask Lemmygrad

I've learned a decent amount about this in the past. Like others have said, it's about living somewhere without a legitimate grocery store (no fresh produce) within some radius, so the residents just wind up buying junk from the convenience stores. The sinister twist is that they actually have tried interventions where stores with real food are opened up in underserved areas, but they all go under because the residents are so hooked on junk. Furthermore, they have been eating convenience foods for so long that they no longer know how to cook for their families. It's a truly bleak reality.

Yes, these stores sometimes still carry rice and beans, as well as frozen fruits and vegetables. But the options are limited and you have to be extremely disciplined. Here's a blog that suggests that. Spot-checking dollar general, out of 28 pages of frozen items, I saw 6 frozen vegetable options (and 0 fruit options), and these were probably intended to be side dishes. As for rice and beans, Americans don't really eat those because the western diet is crappy. This shows up in epidemiology studies as the "Hispanic Paradox" because Latinos are the only people in America who regularly eat a healthy bedrock of the diet: rice and beans.

Once again, this problem is a baseline crappy western diet teaming up with an undereducated demographic (some spots have < 50% high school graduate population) that is usually working 60 - 80 hours a week to barely make ends meet, combined with a lack of fresh produce availability, and you get food deserts where people are just trying to make it to tomorrow buying the junk in front of them because it's one of the only sources of solace in their lives.