Cat Nutrition Myths That Persist Despite the Evidence

The image of a cat lapping up a saucer of milk is deeply embedded in popular culture, but veterinary evidence tells a different story. Kittens produce lactase — the enzyme needed to digest lactose — but many cats lose most of that capacity as they mature. Offering cow's milk to an adult cat frequently results in diarrhea, bloating, or stomach cramps. If you want to offer a liquid treat, plain water or a small amount of commercially prepared, lactose-reduced cat milk is a safer choice, and even those should be given sparingly.

The grain-free trend grew partly from the idea that cats, as carnivores, should eat no carbohydrates. While cats do have a limited ability to digest starches compared with dogs, grains in properly formulated cat food are generally well tolerated and are not the source of most feline food sensitivities. More concerning, the FDA has been investigating a potential link between grain-free diets and dilated cardiomyopathy (DCM) — a serious heart condition — in dogs, and some veterinary cardiologists flag similar caution for cats. A grain-free label is not a guarantee of higher protein quality, lower carbohydrates, or better health outcomes.

Obligate carnivore means cats must obtain certain nutrients — like taurine, arachidonic acid, and preformed vitamin A — from animal tissue, because they cannot synthesise adequate amounts themselves. However, feeding plain muscle meat without organ components, bone, or supplementation creates serious nutritional gaps. Taurine deficiency, for example, causes dilated cardiomyopathy and retinal degeneration. A commercially complete and balanced food, whether wet or dry, is formulated to meet these needs. Homemade and raw diets can be done safely, but only when developed with a veterinary nutritionist to ensure completeness.

Cats evolved as desert animals with a naturally low thirst drive, which means they may not drink enough water regardless of diet type. Wet food does help with hydration and is often recommended for cats prone to urinary tract issues or kidney disease. But a healthy cat with constant access to fresh water and fed a nutritionally complete dry kibble can maintain normal hydration. The debate between wet and dry food involves trade-offs around dental health, calorie density, palatability, and cost — not a simple verdict that one format is harmful. Discuss your specific cat's needs with your vet rather than defaulting to a blanket rule.

Many nutritionally complete commercial cat foods are designed to be fed as a sole diet, so strict variety is not always necessary. However, cats fed only a single protein or brand from kittenhood sometimes develop aversions or sensitivities that make dietary transitions difficult later — particularly when a health change requires a prescription diet. Introducing occasional variety between complete foods, or rotating protein sources within complete formulas, can help prevent this. It also reduces the risk of over-reliance on any single formulation that may change or be recalled.

Feline hepatic lipidosis — sometimes called fatty liver disease — occurs when a cat stops eating or drastically reduces food intake, causing the body to mobilise fat reserves faster than the liver can process them. It is one of the most common serious liver diseases in cats and is strongly associated with sudden food restriction, particularly in overweight animals. Safe weight loss in cats must be gradual, typically supervised by a veterinarian using a calorie-controlled, nutritionally complete diet. Never put a cat on a crash diet or abruptly reduce portions without professional guidance.