If your vet has suggested that your cat needs to try a “novel protein” diet because of suspected food allergies? And your vet is suggesting a type of dry food or a canned food with grains or vegetables included to deal with it? May I just put in my two cents here?
I wince a little at a preliminary diagnosis of a cat being ‘allergic’ to a certain kind of meat when they have diarrhea or vomiting – and yet included with whatever the meat in their food we find all kinds of indigestible or species-inappropriate ingredients that an obligate carnivore was never designed to eat.
It’s rather like declaring that if you get a tummy ache after you’ve finished your meal of “bits of metal with broccoli” that you could be ‘allergic’ to the broccoli – and so next time around, you should eat those bits of metal with some carrot to see if you do better.
I’m not saying there aren’t cats who are potentially allergic to certain types of meat protein – but perhaps looking at a more likely dietary culprit makes sense.