Eating litter

My 16 year old cat (female) started eating her litter from her litter box (yuk!). How do I get her to stop? Tried different litters-no avail. The vet ran blood tests etc. and other than the fact that she's elderly and her bodily functions are slowing, he had no advise on what to do about her strange behavioral problem. Does someone have some insight to this? Eating litter just can't be any good.

Disgusting, isn't it? My old cat does that, too. No clue as to why. The vet said it won't hurt him, but EEEWWWWWWW!!!!! I make him stop when I catch him. At least he only eats the clean litter I just put in after scooping.

She didn't show anemic? Sometimes when a cat eats litter or licks concrete it is a sign that she is anemic. Don't laugh now, but you could change to rabbit feed. I have used it for substitute litter before when I had a litter eater. At least when the cat ate that, it wasn't harmful for her. She stopped about a week after I switched and then when I gradually started adding litter to her box she wouldn't eat that any more. You know what I am talking about? The green pellets you feed bunnies?

Yeah, that's my main concern, switch to a different litter, one which is digestable and will not hurt the cat when eaten. AKA don't use clay or clumping litter right now.

An alternative... which might make her stop eating it completely, is to use potting soil. Most cats can't resist it, it's so soft, and covers so well. But make sure you get one that's about as clean as can be and free from any toxins.
I've learned that cats like this from the MANY whom used to use our flower beds, lol.

I've personally never had a cat with this problem nor heard of a cat eating the litter (and not being after the poo) so I can't give any further insite.

I have heard of animals eating the feaces for nourishment, but not the clean litter itself!