I was doing some editing yesterday and read that iron deficiencies cause people to eat things like soil, charcoal, laundry starch, etc.
So is that why Rebeca eats dirt in One Hundred Years of Solitude?! Revelations.
Down the internet rabbit hole I went and apparently there are a lot more reasons for geophagia (i.e. the deliberate consumption of earth, clay, etc.) than just a simple iron deficiency. It could have been due to a change in culture (which would have made sense, considering Rebeca arrived in Macondo as an orphan), famine, or a psychiatric disease (which could also fit considering she brought forgetfulness to the town and she only ate dirt when she was feeling really nervous/highly strung).
There are so many things I have missed because of ignorance, though perhaps Márquez didn’t mean any of them. Still, it’s nice to try and understand it all according to my own subjectivity. Maybe I’m due another re-read soon…