[header] How to put your cat on a limited ingredient diet [title] Talk with your vet. [step] A limited ingredient diet has ingredients to which your cat is not allergic. For cats, this diet typically contains a novel protein, which is a protein your cat has not eaten before. 
Examples of potentially novel proteins are venison (deer) and kangaroo meat. When you talk with your vet, tell them the protein source in each food you have fed your cat.