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How We Score

Every dog food on Puglib goes through the same independent method, built on peer reviewed animal nutrition research and the standards US dog food is made to.

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Peer reviewed researchAmino acid scienceAAFCO standardsNo paid placement

In short: Puglib scores each dog food from its label alone. Every ingredient is matched to USDA FoodData Central to measure protein quality on amino acids (the DIAAS method, using dog requirements), protein quantity is measured per calorie against what a dog needs at its life stage, and the fats are checked against the AAFCO nutrient profiles. Together these make the Puglib score from 0 to 10, shown as 1 to 4 bones. For each dog, foods that don't suit its life stage, size, protein avoidances or large breed growth are removed, and the rest are ranked by score, fine tuned for how active the dog is. No brand can pay to be listed or ranked.

  1. We read the label, and only the label

    Every score starts from what the brand prints on the bag: the guaranteed analysis, the full ingredient list in order, the calorie content and the nutritional adequacy statement. All of it is taken from publicly available information on each brand's official US website, so every score can be checked against the bag in your hands.

  2. Every ingredient, matched to USDA data

    Each ingredient is matched to its record in USDA FoodData Central, the U.S. Department of Agriculture's food composition database, which supplies its amino acid profile6. It's then adjusted for how it was processed: meals and other heat processed ingredients don't keep their protein the way fresh ones do4.

    Matches are reviewed by hand. An ingredient we can't confidently identify gets a deliberately cautious value, never a generous guess.

  3. Protein quality, measured on amino acids

    Not all protein is equal. We score it with the amino acid method behind DIAAS, the protein quality standard defined by the FAO2, using dog requirements instead of human ones: each essential amino acid in the food is compared with what dogs need, and the one in shortest supply sets the score1.

    Ingredients near the top of the list count most, because they usually make up most of the food. Limited ingredient diets, built on one or two proteins, are weighted toward those.

  4. Enough protein for your dog's stage of life

    Quality alone isn't enough; quantity matters too. We measure usable protein per calorie, so foods of different energy compare fairly, against what puppies or adult dogs need1.

    The scale is calibrated against the foods actually on the market, so the real differences between good foods show up instead of every food looking the same.

  5. The fats that matter

    A food must meet its fat and essential omega-6 minimums3. On top of that, it earns credit for omega-3s5, which count for more in puppies and seniors, in line with the AAFCO growth profile, which sets a recommended minimum for them3.

    A food that falls short on fat can't make it up anywhere else.

  6. Checked against the AAFCO standards

    Every nutrient the label declares is checked against the AAFCO nutrient profiles that US dog food is formulated to3. Labels guarantee minimums for most nutrients and maximums for a few, so we only claim what the label actually supports, and we cross check the brand's own adequacy statement as an independent test of our reading.

    Good to know: a label is a guarantee, not a lab report of each bag. Regulations allow what's actually in the food to vary within an accepted range of the printed values, so small differences between the label and a given bag are normal, and our scores reflect the label as printed.

  7. One score, shown as bones

    Protein quality and adequacy lead, fat completes the picture, and together they make the Puglib score from 0 to 10. On the cards it reads as bones:

    BonesRatingPuglib score
    4 bonesExcellent8.0 and up
    3 bonesGreat6.5 to 7.9
    2 bonesGood5.0 to 6.4
    1 boneFairbelow 5.0

  8. Matched to your dog

    Your answers narrow the list before anything is ranked. A food is removed if it's for the wrong life stage or size, if its ingredient list mentions a protein you want to avoid anywhere, down to an oil or a broth, or if its label excludes the growth of large breed puppies and yours is one.

    What's left is ranked by score, fine tuned for how active your dog is (the next step), and each card shows the brand's own daily feeding amount for your dog's weight and activity. From that amount we work out how long a bag lasts, and, where prices are available, what each food costs per day rather than per bag. Price never changes a food's score.

  9. Fitted to how active your dog is

    Activity changes how much energy a dog needs, and where that energy should come from. A couch potato does best on a lighter food that gets fewer of its calories from fat, so they can eat a satisfying amount without gaining weight. A working dog does best on an energy dense food that gets more of its calories from fat, the fuel active muscles burn most.

    Protein is the one thing activity doesn't lower: a dog's protein need is set by its size, not by how much it eats, so a less active dog eating fewer calories needs at least as much protein in each of them. Every food is checked to give your dog enough protein at the amount it will eat.

    Each card shows an Energy Match and a Fat Match for your dog. A good match moves a food up your dog's list and a poor one down, by a small, capped amount, so it reorders foods of similar quality rather than overturning the scores. For a dog of everyday activity the order doesn't change, and a match never changes a food's Puglib score or bones.

Independent, start to finish

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Questions

Short answers to what people ask most, from how the score works to who we are, are in our frequently asked questions. You can also compare foods for your own dog.

References

The research, standards and data our method is built on. Feeding amounts come from each brand's published feeding chart.

  1. Templeman, J. R., & Shoveller, A. K. (2022). Digestible indispensable amino acid scores of animal and plant ingredients potentially used in dog diet formulation: how this protein quality metric is affected by ingredient characteristics and reference amino acid profile. Journal of Animal Science, 100(11), skac279. (Source of the National Research Council (2006) canine amino acid patterns and protein requirements we use.)
  2. Bailey, H. M., & Stein, H. H. (2019). Can the digestible indispensable amino acid score methodology decrease protein malnutrition? Animal Frontiers, 9(4). (Presents the FAO (2013) DIAAS method.)
  3. AAFCO. Methods for Substantiating Nutritional Adequacy of Dog and Cat Foods, including the AAFCO Dog and Cat Food Nutrient Profiles. Model Bills and Regulations Agenda, Midyear 2015, Attachment A: proposed revisions to the AAFCO Nutrient Profiles.
  4. Wang, X., & Parsons, C. M. (1998). Effect of raw material source, processing systems, and processing temperatures on amino acid digestibility of meat and bone meals. Poultry Science, 77, 834–841.
  5. Bauer, J. E. (2011). Therapeutic use of fish oils in companion animals. Journal of the American Veterinary Medical Association, 239(11), 1441.
  6. U.S. Department of Agriculture, Agricultural Research Service. USDA FoodData Central: the food composition database each ingredient is matched to for its nutrient and amino acid record.

More in-depth methodology: the equations behind our scoring