A few years ago, media outlets ran a story about some people in Haiti eating pies made primarily of mud. I'd never heard of that before reading the story, but I think that's more a function of what parts of the country my parents are from . I also think that it might have been an old rural custom or survival tool that they would have been ashamed to talk about if they ever did hear about it. Until relatively recently, the soil in Haiti was fertile, even with all the deforestation...so that even the very poor could grow subsistence crops.
The clip and the story have resurfaced a bunch of times.
In Johnny Cochran's autobio, he talked about his mom occasionally doing this in rural Louisiana. I think he said that when he went off to college, he realized his parents weren't exactly wrong in their intentions for doing it.
*My aunt used to eat Argo corn starch too. I always looked at her like she was crazy.