Are we seriously equating enjoying a book series with "weak and soulless bodies?" Most kids will keep up doing the thing they love if we let them.---my 7 year old would stay outside all day long if I didn't say "hey come in for a bit and get some lunch, help pick up your room, it's going to rain...come in now." Whether they are building with Legos all day, reading, drawing, painting, playing a game, riding their bike....eventually a parent will have to say "can you pause, turn off, come in, take a break because now we need to xyz." I don't think there's a parent alive who hasn't had to do that with something. But I would rather keep a healthy perspective about it.
I think there's a way to honor their interests and yet still get them fed and doing some chores without making it punitive, or turning it into something pathological.