When I lived in Nicaragua, poor people understood nutrition. The default meal was Gallo Pinto — a mix of beans and rice with whatever vegetables and spices you might have. Complete protein, high in fiber and really the cheapest combination that was healthy.
To “enhance” Gallo Pinto you might have some combination of tortillas, fresh cheese (cuagada), and, if available, a bit of meat — chicken, beef, pork of fish. And, yes, eating Gallo Pinto three times a day was not unusual.
Here in Guatemala I have seen much less “food sense” among the poor. Not thinking about protein content. Eating all too much white flour pasta. And, really, just looking at the volume of food on a plate rather than any serious consideration of nutrition.
Have you seen the same or have I just been in “different places”? Let me know.