Two pet foods can look similar on the front of the pack while differing in their intended use, energy density, moisture and the detail available about their formulation. A fair comparison starts by deciding which question you want to answer. Are you checking whether both foods suit the same animal and life stage, comparing calories, checking a nutrient, or looking for a declared ingredient? One product can be lower in one nutrient per 100 grams and still provide more of it per calorie or per feeding day.
Start with the same animal and life stage
Check the species statement first. A dog food and a cat food are not interchangeable just because their ingredient lists look alike. Then compare the intended life stage or other stated use. Growing animals, adults and animals with a specific nutritional purpose can have different requirements. A claim such as “all life stages” is also a statement about intended nutritional adequacy, not a promise that the recipe is the best choice for every individual.
Check the product name, exact recipe, format, market and date of the pack or manufacturer page. A brand can sell several recipes with similar names, and a recipe or label can change. If the profile is based on a manufacturer page rather than a purchased pack, read the source and review notes so you know what was checked.
Check whether each food is complete or complementary
A complete food is designed to provide the animal’s daily ration when fed as directed. A complementary food is intended to be combined with other food. A treat, topper or supplement may have a different role. Compare products with the same declared role, or be clear that you are comparing products that serve different purposes. The FEDIAF nutritional guidelines for complete and complementary pet food (opens in a new tab) explain the European nutritional framework for cats and dogs. The label wording and legal framework vary by market, so use the statement on the pack sold in your country.
Allow for moisture before comparing nutrient percentages
Wet and dry products contain very different amounts of water. The nutrient percentages shown on a label are often reported as sold, with that water included. An as-sold comparison can therefore make a wet food appear lower in protein or another nutrient simply because each 100 grams contains more water. The US Food and Drug Administration’s guide to complete and balanced pet food (opens in a new tab) explains how to convert guaranteed analysis figures to a dry-matter basis.
The dry-matter calculation is:
Dry-matter percentage = nutrient percentage as sold ÷ (100 − moisture percentage) × 100.
For an illustration only, suppose Food A lists 30% protein and 10% moisture. Its dry-matter protein value is 30 ÷ 90 × 100, or about 33.3%. Suppose Food B lists 10% protein and 75% moisture. Its dry-matter value is 10 ÷ 25 × 100, or 40%. These are made-up numbers, not product results. The calculation puts the percentages on a more comparable moisture basis, but it does not tell you how much protein your pet eats in a day or whether either recipe is appropriate.
Use the moisture value stated for the same product and market. If moisture or another required value is missing, do not fill the gap with a guess. Ask the manufacturer for the full analysis, or keep the comparison to values that can be checked.
Compare calories as well as percentages
Energy density helps explain how much of each food is needed to supply a similar number of calories. Look for kilocalories per kilogram, per 100 grams, per can or per serving, and convert to one common unit before comparing. If the calorie statement is missing, the manufacturer may be able to provide it. The WSAVA guide to selecting a pet food (opens in a new tab) highlights calorie information and questions owners can ask manufacturers when important details are not on the label.
Feeding directions are a starting point, not a personalised calorie prescription. The amount an individual animal needs depends on factors such as body size, age, activity, neuter status, health and body condition. Do not infer that two foods are equivalent because the suggested cup, pouch or can amounts look similar. A cup of one product may weigh differently from a cup of another, and different packs may use different serving units.
Read the ingredient list for the question it can answer
Ingredient declarations are useful for checking whether a named material appears in the source you are reading. In the United States, the FDA states that ingredients are listed by common or usual name in descending order by weight. The AAFCO guide to reading labels (opens in a new tab) also explains that ingredients are ordered by weight and that the list does not state the exact amount of each ingredient.
Order by weight is not the same as nutritional contribution or quality. Ingredients with more water can weigh more when added to a recipe than concentrated dry ingredients. A label list also does not show every detail needed to judge a recipe, such as the complete nutrient analysis, digestibility, manufacturing controls or the evidence behind a specific claim. The WSAVA manufacturer questions can help you decide what to ask when the pack is not enough.
Use the Evidence.pet tools
In the product directory, choose a species and narrow the records using the available filters. Open the product profiles if you need to check the source, market, product role or review status. Product profiles are label-based records of the information available to us. They are not independent laboratory analyses of every batch.
To compare products, select two to four records using their Compare controls, then open the product comparison tool. You can also go directly to the comparison page and search for products there. It places recorded details side by side and points out differences. It does not decide which product is best for your pet.
For a worked example of the type of information recorded, open the Burns Original Fish & Brown Rice profile. It is a label-based profile for one specific dog-food product, not a recommendation or an independent comparison.
A quick comparison checklist
- Same species, life stage and declared feed role?
- Same product recipe, market and current source?
- Are nutrient figures reported as sold or on a dry-matter basis?
- Do you have calories in the same unit for both foods?
- Are missing details clearly marked instead of assumed?
- Are you using the ingredient list to check declarations, rather than to infer exact amounts or overall quality?
If the animal has a medical condition, is growing, is losing or gaining weight unexpectedly, or has a history of food reactions, use the comparison to prepare questions for a veterinary professional. A label comparison cannot replace advice based on the animal and its full diet.