Feeding a Cat Well

Nutrition is where owners have the most control over a cat's long-term health and the least reliable information. This page sets out what is established, what remains genuinely contested, and how to read a label — without naming a single product, because the useful skill is reading the panel rather than trusting a name.

Start from the animal

Cats are obligate carnivores. That is not a preference, it is a metabolic constraint. Unlike dogs and people, cats cannot efficiently manufacture certain nutrients from plant precursors and must obtain them pre-formed from animal tissue. The best known is taurine, an amino acid whose deficiency causes retinal degeneration and dilated cardiomyopathy — a link established in the 1980s and one of the clearest cause-and-effect stories in companion-animal nutrition. Arachidonic acid, pre-formed vitamin A and vitamin B12 sit in the same category. It is also why a vegetarian diet is not a safe option for a cat in the way it can be for a dog.

Left to itself, a small cat eats mice, birds and insects: a diet high in protein, moderate in fat, low in carbohydrate. Perhaps a tenth of it is plant material, most of that arriving as the stomach contents of prey. Cats have correspondingly limited machinery for handling large carbohydrate loads and run their energy metabolism on protein and fat.

The second fact matters as much. Cats evolved in arid environments and have a weak thirst drive. Natural prey is roughly 65 to 75 per cent water, so a cat is built to take most of its fluid from food rather than from a bowl. A cat eating only dry food, typically under 10 per cent moisture, has a large deficit to make up by drinking, and many cats simply do not.

Wet, dry, or both

This is the question owners ask first, and the honest answer has three parts.

Moisture is a real advantage of wet food. Higher water intake means more dilute urine, which is a meaningful consideration in a species prone to lower urinary tract disease and a serious one for male cats, in whom urethral obstruction is life-threatening.

Dry food is not poison. Complete dry diets meet established nutritional requirements, cost less, keep better, and suit food-puzzle feeding, which is among the better environmental-enrichment tools available. The old claim that ordinary kibble cleans teeth is largely unsupported, although some diets are specifically formulated and tested for a dental effect.

For most households the answer is both. Wet food for the moisture, some dry for convenience and enrichment, portions measured rather than the bowl kept permanently full. The Cornell Feline Health Center guidance on feeding your cat covers the trade-offs in more detail than any manufacturer will.

Reading a label

Three things on a package tell you something. Everything else is marketing, and terms such as premium, gourmet and natural have little or no regulatory meaning.

1. The nutritional adequacy statement

This is the small-print sentence saying the food is complete and balanced for a named life stage — growth, maintenance, or all life stages — and whether that was established by formulation to a published nutrient profile or by a feeding trial. A food without such a statement is a treat or a supplement, whatever the front of the bag implies. How pet food labels are regulated explains what the wording is required to mean.

2. The ingredient list, read as an order

Ingredients are listed by weight before processing, which creates two traps. First, whole meats carry their water with them, so a fresh meat can outrank a dry protein concentrate while contributing less actual protein to the finished food. Second, splitting one ingredient into several fractions moves each fraction further down the list without changing the total. Read the whole list rather than the first line.

One widely repeated claim deserves correction. By-products are not automatically low quality: the category includes organ meats such as liver, heart and kidney, which are nutrient-dense and are exactly what a wild cat eats first. The reasonable objection to by-products is variability, not that they are inherently waste.

3. The guaranteed analysis, converted

Percentages on wet and dry food are not comparable as printed, because one is mostly water. To compare, convert to a dry-matter basis: divide the printed percentage by the total dry matter (100 minus the moisture percentage), then multiply by 100. A tin at 10 per cent protein and 78 per cent moisture is about 45 per cent protein dry-matter — far more than the printed number suggests.

Raw and home-prepared diets

Home-prepared feeding has enthusiastic advocates, and the intuition behind it is reasonable: fresh food of known provenance, minimally processed. The evidence has nonetheless hardened considerably against improvising it.

Published analyses of home-formulated recipes find that a large majority are nutritionally unbalanced — most often in calcium-to-phosphorus ratio, in taurine, or in vitamin content — and the deficits are cumulative and invisible until they are not. Raw meat additionally carries a documented risk of bacterial contamination affecting both the cat and the people in the household, which is why most veterinary associations advise against it where there are young children, elderly people or anyone immunosuppressed.

If you want to feed a home-prepared diet, the responsible route is a recipe formulated by a board-certified veterinary nutritionist for your individual cat, followed precisely rather than improvised around. The commonest and most damaging error is adding fresh muscle meat to a complete commercial food every day: the commercial product is balanced for its own mineral ratios, and unsupplemented meat pulls the whole diet out of balance over months.

Weight, which is the real epidemic

Far more cats are harmed by quiet overfeeding than by any ingredient. Excess weight is associated with diabetes mellitus, osteoarthritis, hepatic lipidosis and reduced lifespan, and it accumulates so gradually that owners genuinely do not see it.

Learn to assess body condition by feel rather than by eye: ribs easily felt under a thin fat covering, a visible waist from above, a slight abdominal tuck from the side. Measure meals rather than filling a bowl. And never crash-diet a cat — rapid weight loss in an overweight cat can precipitate hepatic lipidosis, which is dangerous and expensive. Reduction should be gradual and supervised; the AAHA nutrition and weight management guidelines set out sensible rates.

Changing a cat's food

Cats form food preferences early and can be genuinely intractable about them. Transition over seven to ten days, mixing an increasing proportion of the new food into the old. Warming wet food slightly to body temperature helps, as does feeding away from a busy thoroughfare in the house.

If a cat refuses outright, do not simply wait it out. A cat that stops eating for more than a day or two, particularly an overweight one, is at real risk of hepatic lipidosis. That is a veterinary matter, not a contest of wills.

Things that are not food

A short list worth knowing: lilies of the Lilium and Hemerocallis genera are acutely nephrotoxic to cats, including the pollen; onion, garlic and chives damage red blood cells; grapes and raisins are associated with kidney injury; and paracetamol is lethal to cats at doses a person would consider trivial. Milk is not toxic but most adult cats are lactose intolerant, and it displaces balanced food with empty calories.

The short version

• Feed a complete diet carrying an adequacy statement for the right life stage.
• Get water into the cat — wet food, more bowls, a fountain if it helps.
• Measure portions and keep the cat lean; this matters more than the brand.
• Read the ingredient list as an order, and convert to dry matter before comparing.
• Treat home-prepared feeding as a project needing professional formulation, not an improvisation.
• Take any change in appetite seriously, and early.

Next in the library: vaccination and declawing.