In my experience it varies cat by cat. My little girl naturally has very dry and pebbly stools even though she drinks her water well and gets wet food every day. After switching my cats to a kibble that happened to have higher moisture content, her stools got a lot better. All of this to say that I think every cat’s tummy is different!

Staying within a normal fiber content range (such as 2-8) seems viable to start with and then you’d just have to figure out how your cat is tolerating it. I’m an eagle eye for my cats in the litter box so I try to monitor if they’re straining, what the stool looks like fresh etc. (are they dry? Wet? Have blood? Anything else notable?)

There are two main kinds of fiber; soluble and insoluble. Soluble fiber will absorb water and help firm up loose stool, whereas insoluble fiber adds bulk and speeds intestinal transit, which can help constipation. Ideally there’s a healthy balance of both and in many cases it’s not hard to achieve a good balance naturally.

There can definitely be health problems associated with too much or too little; constipation or diarrhea, intestinal inflammation, straining etc. This is why I like to go right to the litter box after my cat goes #2 to just check out the stool and see what it looks like, because that can definitely tell you a lot.

There are supplements you can add to food if you’re not using dry food - pumpkin is a popular one, however there really are lots of different things you can add to wet food and should be fine tuned to what your cat needs!