Cat Nutrition Myths That Veterinarians Wish Would Disappear

The image of a cat lapping contentedly at a bowl of milk is deeply embedded in popular culture, but it does not hold up biologically. Kittens produce the enzyme lactase to digest their mother's milk, but lactase production drops significantly after weaning. By adulthood, most cats lack enough lactase to process the lactose in cow's milk, which leads to gastrointestinal upset. Water is what cats need for hydration, and any dairy treats should be given only in very small amounts if your individual cat shows no signs of intolerance.

The grain-free trend grew partly out of the assumption that grains are filler ingredients cats cannot digest. Cats do have limited capacity to digest large amounts of carbohydrate, but small amounts of grain are generally well tolerated. More relevant is the fact that many grain-free products replace corn or wheat with peas, lentils, or sweet potato, ingredients that can be equally high in carbohydrates. The FDA has also investigated a possible association between legume-heavy diets and dilated cardiomyopathy in dogs, prompting broader caution. For cats, the overall nutrient profile matters far more than whether a diet contains grain. For a thorough look at how different food formats compare, see how wet, dry, and raw diets differ for cats.

In the wild, cats get most of their moisture from the animals they eat, which are roughly 70 percent water. Kibble typically contains only 8 to 10 percent moisture. A cat relying entirely on dry food must compensate by drinking considerably more water than comes naturally to them, and many cats simply do not. Chronic mild dehydration contributes to urinary tract disease and kidney problems, conditions that are among the most common reasons cats visit veterinary clinics. Incorporating wet food, even partially, increases daily moisture intake meaningfully.

While some cats do moderate their intake instinctively, indoor cats with sedentary lifestyles and constant food access frequently consume more calories than they expend. Feline obesity is now one of the most common nutritional disorders veterinarians see, with associated risks including diabetes, joint disease, and a shorter lifespan. Measured meal feeding, rather than leaving food out all day, gives owners better control over caloric intake. If your cat eats less than usual for more than a day or two, a vet visit is warranted rather than assuming the cat is simply not hungry.

Dogs can generally tolerate short fasts without severe consequences. Cats cannot. When a cat stops eating, the body mobilizes fat reserves to meet energy needs, but cats process fat inefficiently, and fat accumulates in the liver. Hepatic lipidosis, also called fatty liver disease, can develop within two to three days of inadequate food intake and becomes life-threatening without prompt treatment. Food refusal in a cat should prompt a call to your veterinarian within 24 hours, not a waiting game to see if the cat gives in.

Proponents of raw feeding often argue that wild cats eat raw prey, so domestic cats should be fine with raw meat. Wild prey and commercial raw meat differ substantially in bacterial load, handling history, and storage conditions. Raw poultry and beef can carry Salmonella, Listeria, and E. coli, pathogens that can sicken cats and transfer to humans through contact with food bowls, surfaces, or the cat's feces. Any raw feeding approach should involve strict food-safety protocols and ideally a consultation with a veterinary nutritionist. The topic of raw feeding for pets is covered in more depth in our companion article on how dog owners weigh raw, kibble, and fresh-cooked diets, where many of the same safety principles apply.