system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is chewing on ice bad for your teeth?

I love chewing on ice but every time I do there’s a little guilty voice that tells me I shouldn’t because I’ve heard it’s bad for your teeth.  I’ve also heard that chewing ice can also mean that you’re anemic?
gpt
A craving or frequent desire to chew on ice can indeed indicate anemia.  If this sounds like you, ask your doctor for a blood test.

Ice is hard, and unless it's very thin, doesn't break super-easily.  Our teeth can handle chewing on hard stuff sometimes, but if you do it frequently it can wear down your teeth or even cause fractures.