Glossary

Limited-ingredient diet

A food built around one protein and one carbohydrate source to reduce exposure, often used to look for a food allergy.

Also called: LID, limited ingredient dog food, single-protein diet, simple ingredient diet

A limited-ingredient diet, or LID, uses a small number of ingredients, typically one animal protein and one carbohydrate, with few additives. The idea is to cut down on what a sensitive dog is exposed to, which makes it a common choice for dogs with suspected food allergy or intolerance.

Not every food with this label is suited to a true elimination trial. Over-the-counter versions can carry trace amounts of other proteins from shared equipment or a flavoring, which can fool the test. Vets who diagnose a food allergy often prefer a hydrolyzed or true novel-protein diet used for several weeks without treats or flavored medicines.

A limited-ingredient diet must still be complete and balanced. Keep the label in mind and ask a veterinarian before using one, since itching can have other causes.

Last reviewed November 8, 2026

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Related terms

Food allergy An immune reaction to a protein in the diet that usually causes itchy skin and ear problems, and sometimes digestive upset. Novel protein A protein source a dog has never eaten before, used in elimination diets because the immune system has not learned to react to it. Hydrolyzed protein diet A veterinary diet whose proteins are chopped into pieces too small for the immune system to recognize, used to diagnose and manage food allergy. Prescription diet A food formulated to help manage a medical condition such as kidney disease or food allergy, fed under veterinary supervision.