How much should I feed my cat?

The resting energy requirement (RER) is what a cat burns at rest. The 2021 AAHA Nutrition and Weight Management Guidelines use the same formula for cats as for dogs: 70 x body weight in kg to the power 0.75. The Merck Veterinary Manual says this exponential formula can be used at any body weight, while the simpler 30 x kg + 70 is only for animals between 2 and 45 kg, which rules it out for kittens and cats under 2 kg.

The maintenance energy requirement (MER) is the RER times a life-stage factor. AAHA gives ranges, shown below. Merck's table gives single values: 1.2 for a neutered adult, 1.4 for an intact adult, 1.0 for an obesity-prone adult and 2.5 for a kitten, which may also be fed free choice. Merck's values sit at the low end of AAHA's ranges, a useful hint that most indoor cats need less than owners expect.

AAHA adds that sedentary or indoor pets may need fewer calories than these factors suggest. A cat that lives in a flat and sleeps most of the day is that cat.

WSAVA's Global Nutrition Committee says individual cats can need up to 50% more or less than any starting estimate; Merck says as much as 30% either way. So the calculator gives a range. Start in the middle for a typical neutered indoor cat, and nearer the bottom if it is already round.

The check is the body condition score, on WSAVA's 9-point scale: 4 to 5 out of 9 is ideal, under 4 underweight and over 5 overweight. Your vet can teach you to score your cat by feel and by eye. Cornell's Feline Health Center calls obesity the most common nutrition-related problem in cats and links it to arthritis and diabetes, so ask your vet what your cat's ideal weight is and feed for that.

The feeding guide on the pack is a fair starting point too, WSAVA says. If its figure and the calculator's are far apart, use the lower and watch the body condition score.

WSAVA notes that calorie information is only required on pet food labels in the United States. Look for it on your pack anyway; if it is missing, WSAVA's advice is to contact the manufacturer, who should be able to give it or work it out from the analysis. Without it the calculator cannot give grams, so follow the pack's feeding guide and your vet.

In many Indian homes a cat gets bits of boiled fish or chicken from the family's meal. Plain cooked meat or fish counts as a treat in the 10% share; anything cooked with onion or garlic should not be shared at all, as WSAVA lists both among foods toxic to pets. A full home-cooked diet needs a recipe from a veterinary nutritionist, as Merck advises, because cats need nutrients that are easy to miss.

If a sitter or a drop-in visitor is feeding your cat while you travel, write down the grams of each food, the meal times and the treat limit on the care sheet. Ask them to tell you at once if your cat eats much less than usual: WSAVA says a pet not eating enough to hold its weight needs a vet as soon as possible.