Why Cat Food Labels Deserve Extra Attention
Cats are obligate carnivores. Unlike dogs, they cannot meet their nutritional requirements from plant sources, and they are unable to synthesise several nutrients that other mammals produce themselves. This makes choosing the right cat food more than a matter of preference — it is a matter of biological necessity. Reading the label correctly is one of the most important things you can do for your cat's long-term health.
Cat food sold in the European Union is regulated under EU Regulation 767/2009, the same framework that governs dog food. The UK retained broadly equivalent rules after Brexit. This legislation sets out what must appear on every label, in what format, and in what order. Understanding these rules helps you evaluate cat food objectively rather than relying on packaging design or marketing language.
The Most Important Label Check: Complete or Complementary?
The single most consequential piece of information on a cat food label is whether it is classified as a "complete" or "complementary" food. This is legally required to appear on every pack, yet it is routinely missed by owners.
A complete food provides all the nutrients a cat needs when fed as the sole diet at the correct daily amount. A complementary food does not. It must be combined with other foods to achieve nutritional balance. Treats, most toppers, and many mixer products are complementary. Some pouches and trays — particularly those marketed as "in sauce" or "in jelly" — are also complementary, not complete.
A very common and serious mistake is feeding a complementary food as the primary or only diet. Over weeks and months this leads to nutritional deficiencies, some of which — particularly taurine deficiency — can cause irreversible damage. Before purchasing any cat food, check this designation first.
Taurine: The Non-Negotiable Nutrient
Taurine is an amino acid that is essential for cats. Unlike most mammals, cats cannot synthesise taurine in sufficient quantities from other amino acids — they must obtain it directly from their diet. Taurine deficiency causes dilated cardiomyopathy (a potentially fatal heart condition), retinal degeneration leading to blindness, and reproductive failure in breeding queens.
Taurine is found naturally in animal muscle meat, particularly heart and dark meat. It is absent from plant sources, which is one of the core reasons why vegan diets are dangerous for cats — not a matter of opinion or preference, but of established veterinary science. Taurine is also sensitive to heat: raw or poorly cooked home-prepared diets can destroy taurine, and diets based on raw fish are particularly problematic as raw fish contains enzymes that degrade taurine.
Taurine is not required to appear in the analytical constituents on a cat food label, but any reputable complete cat food will include supplemental taurine to ensure adequacy. If you are in doubt, contact the manufacturer to confirm the taurine content of the food.
Why Cats Cannot Thrive on Plant-Based Diets
The obligate carnivore status of cats has specific biochemical consequences that go beyond taurine:
- Vitamin A: cats cannot convert beta-carotene from plants into vitamin A (retinol) the way dogs and humans can. They require preformed vitamin A from animal sources such as liver.
- Arachidonic acid: cats cannot synthesise this essential fatty acid from linoleic acid as other mammals do. It must come directly from animal tissue.
- Niacin: cats have a very limited ability to synthesise niacin from tryptophan and require dietary niacin from animal sources.
- Taurine: as described above.
These are not minor gaps that can be filled by supplements alone without great care. They represent fundamental metabolic differences that make cats dependent on animal-derived nutrition for health and survival.
Moisture Content and Urinary Health
Cats evolved in arid environments and have a naturally low thirst drive. In the wild, they obtain most of their water intake from prey animals, which are approximately 70 per cent moisture. Domestic cats fed exclusively on dry food frequently do not compensate by drinking enough water from a bowl, leading to chronic mild dehydration. This is strongly associated with the development of lower urinary tract disease, including cystitis, urethral blockages in male cats, and the formation of urinary crystals.
Wet food, with a moisture content of around 70 to 80 per cent, much more closely matches the moisture content of a cat's natural prey. For cats with a history of urinary problems, chronic kidney disease, or diabetes, feeding primarily wet food is often a central part of the management plan recommended by vets. Even for healthy cats, incorporating wet food regularly is generally considered beneficial for urinary tract health.
Mandatory Label Information Under EU Regulation 767/2009
The same legal requirements that apply to dog food apply to cat food:
- Species designation (cat food)
- Net quantity
- Best before date and batch number
- Manufacturer name and address
- Complete or complementary status
- Ingredient list in descending order by weight before processing
- Analytical constituents: crude protein, crude fat, crude fibre, moisture, and crude ash
- Any additives required to be declared by category and name
Life Stage Claims
Life stage designations on cat food — kitten, adult, senior — must meet the nutritional profiles specified in FEDIAF (the European Pet Food Industry Federation) guidelines for that stage. Kitten foods are formulated with higher levels of protein, fat, taurine, and DHA to support growth and neurological development. They must be fed until a kitten reaches maturity, typically around 12 months for most breeds and up to 18 to 24 months for large breeds such as Maine Coons or Ragdolls.
Senior cat foods are typically formulated with reduced phosphorus levels to support kidney health — kidney disease is extremely common in older cats — and may have adjusted calorie density to prevent weight loss in cats with reduced appetite. If your vet has diagnosed early-stage kidney disease, they may recommend a specific veterinary renal diet rather than an over-the-counter senior food.
Ash Content and Urinary Health
Higher ash content historically associated with struvite crystal formation and urinary problems in cats. Ash is the mineral residue that remains after the food is incinerated — it reflects the overall mineral content including calcium, phosphorus, magnesium, and others. Modern wet cat foods are generally formulated to maintain correct urinary pH and magnesium levels that minimise struvite crystal risk, but checking ash content remains relevant if your cat has a history of urinary disease. A vet or veterinary nutritionist can advise on appropriate ash and magnesium levels for individual cases.
Nutritional Standards: FEDIAF and AAFCO
You may see references to both FEDIAF and AAFCO nutritional standards on premium cat food labels. AAFCO is the Association of American Feed Control Officials and sets the nutritional standards used in the United States. FEDIAF sets the equivalent standards for the EU and UK. Both are scientifically grounded and regularly updated, and both are used by reputable brands as a benchmark for complete and balanced nutrition. In the EU and UK market, FEDIAF is the primary relevant standard, but a food meeting AAFCO standards will typically meet FEDIAF requirements as well. Look for an explicit nutritional adequacy statement referencing one or both of these bodies as confirmation that the food has been formulated to a recognised standard.
Reading the Label in Practice
When evaluating any cat food, work through these steps in order: confirm the food is complete, check that an animal protein source is the first ingredient, review the moisture content for your cat's needs, consider the life stage designation, and look for a FEDIAF nutritional adequacy statement. These five steps give you far more useful information than any amount of front-of-pack marketing language.