The main ingredient in Purina One is lamb which is a good start. Not as good as saying lamb meal but lamb none the less. From there it goes downhill much like their other products except they added oatmeal to the diet as well which is a plus but much further down their list of ingredients.
Purina for some odd reason likes adding brewers rice to all their products in great quantity. There is no nutritional value in the brewers rice and this should be excluded or in smaller amounts. They also make use of two types of corn products. Corn gluten then again whole corn. There is simply put too much grain in their products. As stated this is much better than the other products they offer.
They have lamb as the main ingredient but there is simply too much grain in this product.
Ingredients: Lamb (natural source of glucosamine), brewers rice, corn gluten meal, whole grain corn, poultry by-product meal (natural source of glucosamine), oatmeal, animal fat preserved with mixed-tocopherols (form of Vitamin E), lamb meal, animal digest, potassium chloride, calcium carbonate, calcium phosphate, salt, caramel color, L-Lysine monohydrochloride, choline chloride, zinc sulfate, ferrous sulfate, Vitamin E supplement, manganese sulfate, niacin, Vitamin A supplement, calcium pantothenate, thiamine mononitrate, copper sulfate, riboflavin supplement, Vitamin B-12 supplement, pyridoxine hydrochloride, garlic oil, folic acid, Vitamin D-3 supplement, calcium iodate, biotin, menadione sodium bisulfite complex (source of Vitamin K activity), sodium selenite