[JackFr]

I don't think that's necessarily true. Rice and beans are cheaper than mac & cheese. (Though only marginally better nutritionally.)

I think a lot of it has to do with availability. People in poverty are typically less well served by large grocery stores, and are more likely to shop in convenience stores. Convenience stores are less like to stock low margin products like bulk rice and dried beans, and more likely to stock higher margin processed foods.

I'm not an expert though, could be many factors.

[watwut]

The taste difference between rice or beans with nothing more in it (no vegetables, meat, etc) is pretty massive. Also, mac&cheese makes you more satiated then rice. Rice is mostly sacharids (no fat, no protein, no nothing) - so it gives you energy only for short time, then you are tired and need to eat again.

I know, because I cook/eat a lot of rice and beans. I have add a lot of fruits etc in between meals to feel good. The dirt cheap vegetarian foods people tend to suggest are not really foods you would eat long term without feeling hungry and tired a lot. With that in mind, I can see someone whose life generally sux to at least eat food that makes them less miserable.

Also, mac&cheese is quick cooking and beans are not when you cook them.

[Retric]

Rice and Beans needs to be mostly Beans to be filling. 30% Rice 70% Beans is tasty and filling where 70% Rice and 30% Beans is not.

It also has other health benefits: https://academic.oup.com/ajcn/article/94/3/869/4411867

[watwut]

Yeah, but I like bean soup with a lot of beans in it which has +vegetables+bacon. I did tried to make myself full from beans but mostly, but it does not really work and lasts shorter then normal meal with meat.

As in, it is ok lunch, but I am hunger in shorter time then with meat or say mac&cheese. Importantly, when I try to eat only that for 2-3 days, it does not work at all.

[Kalium]

My experience with convenience stores is that they generally do stock items like beans and rice. They sell in time, and until they do they're shelf-stable more or less forever. And you can sell in small quantities - maybe 8oz or a pound for $2 - that hide the markup behind small numbers. Especially in areas where they're staples.

It's fresh fruit and veggies that you will tend to see the least of in c-stores.