Lamb and rice foods don’t prevent allergies. Lamb and rice foods were initially created to address common food allergies to proteins like chicken and beef. The reason such diets worked was not due to any particular properties of lamb or rice, but simply because most animals had never been exposed to them; they were “novel” ingredients. It takes exposure over time to develop a food allergy. A dog or cat who develops a food allergy in the first place is apt to become allergic to any food if they eat it over a long period of time.