IBS diagnosis

So after catching a bit of bloody like mucus I'm my cats' stool I took her to the vet. No parasites and really no symptoms aside from that the vet diagnosed her with IBS. Or at least he said it was something similar. Sorry a bit vague since it was an early appointment and I was.. well tired.

Anyway other than that and being a bit overweight he said to try to find a different food since he wanted to try that before anything major. He also suggested not going too crazy with prebiotic either..

But he never gave me any food recommendations and it's too late to ask what I should swap too. I'm not sure if this is a vet related question but I thought it'd get taken down in the cat advice sub. Does anyone know what I could swap too? Preferably no chicken flavors as for some reason my girls will absolutely refuse to eat anything chicken flavor. I don't know why it's frustrating lol.