How to read pet food labels and which parts are regulated

The most useful line on a bag of pet food is usually in small print on the back: the nutritional adequacy statement, which says whether the food is complete and balanced, for which species and for which life stage. The Association of American Feed Control Officials (AAFCO) calls it perhaps the most important part of a label. Much of the front of the bag, by contrast, is optional marketing. Reading a label well means knowing which parts are regulated, what the regulated wording actually promises, and which popular words promise nothing.

Who sets the rules

In the United States, the FDA's labeling requirements apply to all pet food sold across state lines, and most states have adopted AAFCO's model pet food regulations into their own law. AAFCO itself is not a regulator, but its model regulations are the practical standard, and they define ingredient names, product-name rules and the nutrient profiles that "complete and balanced" refers to.

In the European Union the legal rules come from EU feed legislation. FEDIAF, the European pet food industry federation, publishes a Code of Good Labelling Practice that explains those rules with examples and is validated by the EU and member states. EU labels follow different wording and thresholds (for example, "with chicken" means at least 4% chicken in the EU), so the specific rules below are the US ones.

The product name

Under the AAFCO model rules, small words in the name set how much of an ingredient the food must contain:

So "with chicken" and "chicken dinner" describe very different foods. Where two ingredients are named, as in "chicken and rice", the one listed first must be present in the greater amount.

The ingredient list

Ingredients must be listed in descending order by weight, using their AAFCO names, all in the same type size and style. The list shows order, not amounts, and it has some quirks worth knowing.

Fresh meat versus meal

The weights include the water in each ingredient. Fresh chicken is mostly water, so it can sit at the top of the list and still supply less protein to the finished kibble than its position suggests. A meal, such as chicken meal, has been rendered to remove water and fat before it is weighed. Its place on the list reflects a much more concentrated ingredient. Neither is better in principle. Both are legitimate protein sources, and the guaranteed analysis is a better guide to how much protein the food holds.

The same ingredient under several names

Because each ingredient is listed separately, one crop can appear several times, for example as ground corn, corn gluten meal and corn bran. Individually each sits lower on the list than it would as a single entry, but together they can outweigh the ingredient at the top. That is not illegal or necessarily harmful. It is a reason to read the whole list rather than the first line.

By-products and species

AAFCO defines by-products as secondary products made alongside a principal product, and its position is that they can be used safely to provide nutrition. Many never carry the word: wheat bran is a by-product of flour milling. For animal ingredients, the rules require the species to be declared if meat or meat by-products come from anything other than cattle, pigs, sheep or goats. Vague collective terms such as "animal protein products" are not allowed on US pet food labels. Whether to choose foods with or without animal by-products is a matter of preference and budget more than of safety.

The guaranteed analysis

A US label's guaranteed analysis must state four values: minimum crude protein, minimum crude fat, maximum crude fiber and maximum moisture. EU labels list "analytical constituents" instead, which include crude ash and give moisture only when it is above 14%. "Crude" describes the lab method, not the quality of the ingredient. Crude protein, for instance, is calculated from the nitrogen content. Because these are minimums and maximums, the real content can differ from the printed number in the permitted direction.

Comparing wet and dry food

These values are given "as fed", including water, which makes wet and dry foods hard to compare. The Merck Veterinary Manual gives canned food as 60% to more than 87% water and dry food as 3% to 11%. To compare them, convert to a dry matter basis:

A wet food with 8% protein and 78% moisture works out at 8 ÷ 22 × 100, about 36% protein on a dry matter basis. A kibble with 26% protein and 10% moisture works out at 26 ÷ 90 × 100, about 29%. On the bag the kibble looks richer in protein. Once the water is taken out, the wet food has more.

Calorie content

US labels must show calorie content in kilocalories per kilogram of food and per familiar unit, such as a cup or a can. This is the number to use when working out portions and when comparing value between two foods, since a denser food means a smaller portion. Feeding directions on the bag are, in AAFCO's words, guidelines that may need modification for a particular pet. An adult that gains or loses weight without meaning to is being fed the wrong amount.

The nutritional adequacy statement

"Complete" means the food contains all the required nutrients. "Balanced" means they are present in the correct ratios. A complete and balanced food can be the animal's only diet. A food labeled "for intermittent or supplemental feeding only" does not meet those standards, and nor do most treats and toppers.

Life stage

AAFCO recognizes gestation and lactation, growth, maintenance, and all life stages. An "all life stages" food has to be suitable for growth and nursing as well as maintenance, so it carries feeding directions for each. That makes it an acceptable puppy or kitten food, except for a puppy expected to weigh 70 lb (32 kg) or more as an adult, which needs a food whose statement includes growth of large-size dogs. For a settled adult, a maintenance food is often the simpler choice, with portions checked against body weight.

Feeding trial or formulation

The statement also shows how adequacy was established. "Formulated to meet the nutritional levels established by the AAFCO Dog (or Cat) Food Nutrient Profiles" means the recipe was formulated to meet the nutrient levels in that profile, without a feeding trial. "Animal feeding tests using AAFCO procedures substantiate…" means the food has been through a standardized feeding trial in dogs or cats. A rarer third wording, "comparable to a product which has been substantiated using AAFCO feeding tests", covers a "family" product similar to one that was tested. All are legal routes to a complete and balanced claim, and a feeding trial adds direct evidence that animals do well on the food.

Marketing words

Natural

AAFCO defines natural as derived solely from plant, animal or mined sources, which may be heated, rendered, extracted or fermented, but not produced by a chemically synthetic process. Most pet food ingredients qualify. Synthetic vitamins, minerals and preservatives such as BHA and BHT do not, so a food that contains synthetic vitamins or minerals can be called natural only with a disclaimer such as "with added vitamins, minerals and trace nutrients". The FDA has not defined natural for pet food, and AAFCO notes that nothing in the definition makes natural ingredients safer.

Premium and human-grade

According to AAFCO's consumer FAQ, "premium" is a totally unregulated term in feed law, and a premium pet food has no requirements that differ from any other. "Human-grade" is different: AAFCO has specific guidelines for when a food may carry it. Even so, a human-grade claim says nothing about whether the diet is complete and balanced. That still depends on the adequacy statement.

Grain-free

Grain-free describes what is absent, not what is better. The most commonly reported food allergens in dogs, according to a review of published cases, are beef, dairy, chicken and wheat, so the trigger is usually an animal protein rather than grain, and a grain-free food made with the same protein will not help. In 2018 the FDA also began investigating reports of dilated cardiomyopathy in dogs eating certain diets, many of them grain-free with peas, lentils, other pulses or potatoes among the main ingredients. The agency has said that the reports alone cannot establish cause, and in December 2022 it stopped issuing public updates until there is meaningful new science. The question remains open, and it is a reason to discuss a grain-free diet with a vet rather than choose one by default.

A short checklist

1. Species and life stage: a complete and balanced statement that matches the animal in front of you.
2. How adequacy was shown: formulation or feeding trial, stated on the label.
3. Calorie content: kcal per kilogram and per cup or can, used to set portions.
4. Dry matter comparison: when choosing between wet and dry foods, convert the panel values first.
5. The name rule: "beef", "beef dinner", "with beef" and "beef flavor" promise very different amounts.
6. A reachable manufacturer: the label must name who is responsible for the product, so questions about formulation, testing and quality control can go straight to them.

Sources

1. Reading labels: how to understand a dog or cat food label. Association of American Feed Control Officials.
2. Labelling: FEDIAF Code of Good Labelling Practice. FEDIAF European Pet Food.
3. Byproducts. Association of American Feed Control Officials.
4. Nutritional requirements of small animals. Merck Veterinary Manual.
5. Natural. Association of American Feed Control Officials.
6. Frequently asked questions. Association of American Feed Control Officials.
7. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Veterinary Research, 2016.
8. FDA investigation into potential link between certain diets and canine dilated cardiomyopathy. U.S. Food and Drug Administration.