Ripley did that for the first six months of her life, and ugh was it disgusting. Putting some crushed pineapple in her food worked for about a week, then I guess she decided the poo was worth chowing down on anyway.
Randomly, for her 6 month "birthday" I bought some beef marrow bones from the store (about $6 for 7-8 of them from the butcher's section) and I give her one every couple of days. Since then she has stopped completely. Is this because of the bones or because it was just a phase? I don't know, but I can tell you I'm not stopping with the bones, just in case!