Feeding & Nutrition

Walk down the pet food aisle and count how many bags shout about protein. Ancestral. Wolf-inspired. Forty percent meat. The implication is always the same: more protein equals a better food, and if you are not buying the high-protein option, you are letting your animal down.

Nutrition is rarely that simple, and protein in particular gets misrepresented in both directions.

What protein is for

Protein is not primarily an energy source. It is structural material and functional machinery: muscle, skin, coat, enzymes, hormones, antibodies and the constant repair work of the body. Animals need it in adequate amounts continuously because, unlike fat, protein is not stored for later use in any meaningful reserve.

What actually matters is not the crude protein percentage but the amino acids inside it. There are around twenty amino acids, of which ten are essential for dogs and eleven for cats, meaning they must come from the diet.

Cats have that extra one because of taurine, and it is the reason cats are obligate carnivores. Taurine deficiency causes dilated cardiomyopathy and retinal degeneration, and cats cannot make enough of it themselves. Cats also need dietary arginine urgently; a single arginine-deficient meal can cause a dangerous ammonia build-up. They require preformed vitamin A and arachidonic acid from animal tissue too. Dogs, by contrast, are dietary omnivores and can manage on a much wider range of ingredients, including well-formulated plant-based proteins.

The numbers, roughly

Established nutritional guidelines set minimums for complete diets. For adult dog maintenance, the minimum crude protein sits around 18 percent on a dry matter basis, rising to about 22 percent for growth and reproduction. For adult cats the minimum is about 26 percent, rising to around 30 percent for growth.

Those are minimums, not targets. Most commercial foods sit comfortably above them, and typical adult dog foods land between 22 and 30 percent, with cat foods often between 30 and 45 percent.

Protein quality changes the picture entirely. A highly digestible animal protein with a complete amino acid profile at 24 percent delivers more usable nutrition than a poorly digestible protein at 32 percent. Digestibility is rarely printed on the bag, which is one of several reasons why comparing percentages between brands is a blunt instrument.

There is also a labelling trap worth knowing. Wet food percentages look far lower than dry food percentages because wet food is mostly water. A canned food at 10 percent protein and 78 percent moisture is actually around 45 percent protein on a dry matter basis, which is higher than most kibble. To compare fairly, divide the protein percentage by the dry matter percentage, which is 100 minus the moisture.

The kidney myth that will not die

For decades, owners were told that high protein damages kidneys and that older dogs should be moved onto low-protein food as a precaution. This has been thoroughly tested and it does not hold up in healthy animals. Studies following dogs on high-protein diets over years found no evidence of kidney damage. Healthy kidneys handle protein metabolism without difficulty.

The confusion arose from a genuine finding in animals that already have significant kidney disease. In those patients, dietary management does help, but the crucial restriction is phosphorus, not protein as such. Therapeutic renal diets provide moderate amounts of very high quality protein alongside markedly reduced phosphorus, because it is phosphorus that drives progression.

Restricting protein in a healthy senior is actually counterproductive. Older animals become less efficient at using dietary protein and lose muscle mass with age, a process comparable to sarcopenia in people. Many veterinary nutritionists now recommend that healthy seniors receive the same or slightly more protein than younger adults, with calories controlled instead.

When more protein genuinely helps

Growing puppies and kittens need higher protein for tissue building. Pregnant and nursing animals need substantially more, since a lactating queen or bitch is manufacturing milk at extraordinary rates.

Working and sporting dogs in hard training benefit from higher protein for muscle repair, alongside higher fat for endurance energy.

Animals recovering from surgery, injury or serious illness have increased protein requirements for tissue healing and immune function.

Weight loss diets are an interesting case. Higher protein during calorie restriction preserves lean muscle mass while fat is lost, and it improves satiety, so the animal feels less deprived. This is one of the clearest arguments for higher protein in a practical setting.

When high protein is a poor choice

Dogs with diagnosed chronic kidney disease at later stages need a properly formulated renal diet rather than a high-protein food, and this should be guided by blood results rather than guesswork.

Animals with liver disease, particularly those with hepatic encephalopathy or portosystemic shunts, need carefully controlled protein because they cannot process ammonia properly.

Dogs prone to urate stones, notably Dalmatians with their unusual purine metabolism, need purine-restricted diets, which limits certain protein sources.

And here is the practical one that affects the most households: high-protein foods are frequently high-calorie foods too. Feed a very rich food at the same volume as a moderate one, and you get a fat pet. Obesity harms more animals than protein levels ever will.

Reading a label like a sceptic

Ignore the front of the bag entirely. It is advertising.

On the back, find the statement confirming the food is complete and balanced for a specific life stage under a recognised standard, and note whether that was established through feeding trials or by formulation. Feeding trials are the stronger evidence.

Look at the first several ingredients, remembering they are listed by weight before cooking, so fresh meat at 70 percent water can appear higher than it deserves. A named meat meal, which is already dehydrated, is a concentrated protein source despite sounding less appealing.

Ingredient splitting is a common trick. Listing peas, pea protein and pea fibre separately keeps each individual entry lower down the list than the total plant content justifies.

Then, honestly, stop obsessing. A complete, balanced food from a manufacturer that employs qualified nutritionists and conducts quality control will meet your animal's protein needs comfortably. The bigger levers on your pet's health are portion size, body condition, dental care and exercise, and none of those are printed on the front of the bag.