Simple Food ProjectFood for Cats

The most common protein in pet food, and for dogs one of the most common food allergens, with beef and dairy. If chicken is what your pet reacts to, it hides everywhere: chicken fat, chicken broth, chicken meal, natural flavor. On a label, chicken listed first is weighed with its water still in, so a food leading with fresh chicken often has less chicken protein than one leading with chicken meal. Neither is better; they are different measures.

A poultry protein, similar to chicken in nutrition and usually a little leaner. Fresh or deboned turkey is mostly water and ranks higher on the label than its dry contribution; turkey meal is the concentrated form. Turkey is often used as an alternative for pets that react to chicken, but the two are related birds and some pets react to both, so it is not a guaranteed swap.

A plant source of omega-3 fat (alpha-linolenic acid) and fiber, used in about a third of dog foods for coat and stool quality. Dogs and cats convert plant omega-3 to the useful forms inefficiently, so fish oil does the job better. Flax is not a documented common allergen, though some pets tolerate it poorly, most often as loose stool. Fine in a food; not a reason to prefer it over one using fish oil.

The liver of the chicken, used both as a nutrient-dense ingredient and as a flavor. It is rich in vitamin A, iron, copper and B vitamins and most pets find it very palatable, which is why it turns up in treats and as a coating on kibble. Because it is chicken, it counts as chicken for a pet with a chicken allergy, even when it appears far down the list.

Heart muscle from the chicken, a lean organ meat rich in taurine, iron and B vitamins. Raw and fresh-food makers use it as a natural source of the taurine cats require. It adds protein without much fat and appears mostly in fresh, frozen and freeze-dried foods. For an allergic pet it is still chicken.

The dried cells of yeast, often a by-product of brewing. It is rich in B vitamins, protein and minerals, improves flavor, and contains compounds that may support gut bacteria. Despite a persistent myth, there is no evidence it repels fleas. Yeast is an uncommon allergen in pets. Yeast culture is a slightly different product, a fermented feed that supplies similar nutrients.