Has anyone ever gone to a LID diet for allergies then added back foods to find out what your dog is allergic to? How does that type of testing work? If you did it, were you successful in eliminating all food allergies? We have two choices. One is to stay with the prescription novel protein diet indefinitely, maybe for the rest of his life. The other is to gradually add back foods and hope we can find out which ones don’t cause allergies, then try to find a food that only includes non allergen foods. It seems that proteins are the primary allergen, so raw is completely out. There could be other secondary allergens.