Cat food for sensitive stomachs

So your vet has already ruled out parasites and infection — that's actually really useful, because it means you're not chasing the wrong thing. A dietary protein elimination trial is the right next step, and it needs to be done properly to give you clean results. Digestive sensitivity in cats is often driven by food intolerance rather than true allergy, and the key is finding a protein source your cat's immune system has never encountered before. Before I point you toward the right food, a couple of quick questions: what symptoms is your Siberian showing — vomiting, loose stools, or something else — and what have they been eating up until now?

That's exactly the right protocol. Hydrolysed protein is often preferable to novel protein for elimination trials because the proteins are broken down so small that the immune system typically can't react to them — even if the original protein source is something your cat has had before. That matters here, since Whiskas and Felix both use chicken and fish fairly interchangeably, so finding a true novel protein he's never had would be tricky. Is he currently a healthy weight, and does he have any other health conditions you're managing?

Good — at a healthy weight with no other conditions, you have a clean run at this. My recommendation is Royal Canin Anallergenic dry cat food. It uses hydrolysed soy protein and hydrolysed feather keratin as its protein sources — ingredients his system almost certainly hasn't encountered, and both are broken down to a molecular level that bypasses typical immune responses. It's specifically designed for elimination trials like the one your vet has prescribed, it's widely available on Amazon UK, and it's one of the few cat foods where the manufacturing process is controlled to avoid cross-contamination with common allergens. For the 8-week trial, this needs to be the only food he gets — no treats, no toppers, nothing else. It's a dry-only food, so if he's used to wet, there may be a few days of adjustment, but most cats accept it well.

For a standard sensitivity issue you'd normally do a gradual transition, but for an elimination trial your vet will usually want a clean break — otherwise you're extending the period before you get a clear read. Switch him over fully from day one, and note the date you started. If symptoms improve within the 8 weeks, that confirms a dietary cause. If they don't improve at all, go back to your vet before the trial ends — there's no point running the full 8 weeks without any change. Keep a simple log of his stools and any vomiting so you have something concrete to report back.

Good luck with it — Siberians tend to be fairly food-motivated, so he should take to it reasonably well. The 8-week commitment is the hard part, but if you stick to it strictly the results will actually tell you something useful. Hope you get a clear answer.