This is Purina's top of the line product, but is still a very low quality  dog food .  It contains small amounts of meatlittle meat and and an large amount of low quality grain ingredients. The by-product and fat are poor quality. Purina ONE contains additives such as menadione sodium bisulfite and caramel color, both proven to be toxic to some degree in animals. Animal digest is another extremely low grade ingredient and can include hooves, feathers, teeth and horns.
Purina ONE Ingredient Analysis

  1. Lamb
  2. Brewers rice
  3. Corn gluten meal
  4. Whole grain corn
  5. Poultry by-product meal

Lamb is a good meat source, but it is the only meat ingredient. When the water is removed for processing it losses at least 70% of its mass, moving it down the ingredient list.

Brewer’s rice, is a low quality grade grain and all of the nutrients have been removed.

Corn gluten meal, is the lowest quality grade of corn you can get.

Whole grain corn, corn is hard for dogs to digest and has been linked to allergies in some dogs.

Poultry by-product meal is an extremely low grade ingredient and includes feet, neck, feathers and undeveloped eggs.

Purina ONE Ingredient List

Lamb, brewers rice, corn gluten meal, whole grain corn, poultry by-product meal, oat meal, animal fat, soy flakes, soybean meal, glycerin, animal digest, calcium phosphate, calcium carbonate, salt, potassium chloride, caramel color, Vitamin E supplement, choline chloride, zinc sulfate, L-Lysine monohydrochloride, ferrous sulfate, sulfur, 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.

Purina ONE Guaranteed Analysis

Guaranteed Analysis describes the nutrient content required by AAFCO labeling standards to be identified on every product package. Since these are guarantees, pet food manufacturers work to formulate diets that meet or exceed the minimum requirements.
Crude Protein (MIN)26.0%Phosphorus (P) (MIN)0.8%
Crude Fat (MIN)16.0%Selenium (Se) (MIN)0.35 mg/kg
Crude Fiber (MAX)3.0%Vitamin A (MIN)13,000 IU/kg
Moisture (MAX)12.0%Vitamin E (MIN)250 IU/kg
Linoleic Acid (MIN)1.4%Glucosamine (MIN)*400 ppm
Calcium (Ca) (MIN)1.0%Omega-6 Fatty Acids (MIN)*1.6%