Issues Adding Wet

I posted a thread a few of weeks ago about adding wet food to my cats diet. I knew her stools were going to change at first but I switched out about 1/3 of her dry for the wet to start and she was having diarrhea and throwing up after a few days. I took her to the vet and he said it was the food so I switched to another food for sensitive stomachs and the same thing happened, not just very soft stools but getting physically ill. I cut out the wet food completely now which has stopped the vomiting and diarrhea but it seems her body is used to getting her mostuire from food already (as I know she should which was a big reason I wanted to add in wet to begin with) so her thirst drive seems low now. This has resulted in constipation and her straining with the occasional out of litter box issue when she manages to get something out. I’m finding random (very dry) poop chunks (never pee) in various places in my house which is frustrating but I’m more frustrated with how uncomfortable Luna must be. When I watch her in the litter box she tries but hasn’t been able to really get anything out and when I haven’t been able to monitor her I come home to find the box empty of poop. She has another appointment for the vet on Tuesday but until then any advice is welcome.

I'd have the vet check for allergies, sometimes cats are allergic to certain ingredients in food.

Is she drinking? make sure she gets some water- vomiting and diarrhea will deydrate her too.

She’s drinking some but not as much as she’s used to or should be. I have a little fountain for her away from her food and let the tap drip but since switching her thirst drive seems to be way down for some reason. Thanks for the advice, I’ll definitely ask the vet if they can do an allergy test on Tuesday!

what foods are you feeding, dry, and wet? Some dry foods have way too much fiber, which can cause constipation, some have way too little fiber, although i think this is more rare, and could cause problems. I find about 4% fiber on a dry basis works well for my cats.

wet food can run the whole range of low to very high fiber. There could also be a common ingredient in the foods that cause her problem. my cats dont do well with much in the way of peas or potatoes. So if all the foods you feed have a common ingredient it might add up and cause a problem?

vet visit is a good idea. keep us updated.