The premium dog foods are free of fillers (grains) and by-products that can cause allergies. However, you have to watch the amount of protien in the foods. Some of the Bison versions can be as high as 35% protien which is great if your dog is a field dog or is very, very active. However, if the dog is more of a house dog, you want to make sure the protien is in the 24% or lower. Protien is like rocket fuel for dogs and can cause weight gain. We have had good luck with Taste of the Wild - lamb for our Brittany who was having allergy issues (i.e. scratching herself all the time). Best part of using the premium foods is that she tends to eat less and the volume of poo is less. So, it seems to help compensate for the higher cost of the food and I don't mind smaller pickups in the yard.