Is My Cat Overweight?

The hands-on check

PDSA suggests running your hands along your cat's sides. The skin should move freely over the ribs, and you should feel the ribs with light touch. Then feel along the back. You should feel the spine and hip bones under the skin without being able to see them.

Also feel the base of the tail for any build-up of fat. Finally, feel under the tummy, which should go in rather than bulge out.

Blue Cross says that in an overweight cat you cannot easily see or feel the ribs. In an average cat they are easily felt under a small layer of fat.

Look from above and from the side

From above, your cat should have a clear waist. From the side, Blue Cross describes a slight tuck at the belly in an average cat, and a podgy belly hanging low in an overweight one. The RSPCA also says the belly should not sag underneath.

International Cat Care describes an obese cat as having a thick layer of fat over the ribs and bony areas, a pendulous "skirt" under the belly and no waist.

Body condition scores and weight

Vets use a body condition score because an ideal weight depends on age and breed. International Cat Care uses a 1 to 5 scale, while PDSA and BSAVA use a 9-point scale. Sources also draw the line between "overweight" and "obese" in different places.

For that reason, there is no single number to aim for at home. BSAVA, a UK professional body, notes that more than one score could be considered optimal for a cat. Ask your vet what is right for yours.

You can weigh your cat at the vet or at home using baby scales. PDSA suggests checking your cat's weight and shape every couple of weeks from kitten age, while Blue Cross suggests weighing every one to two months.

Why cats put on weight

Several everyday things can lead to an overweight cat. Neutered cats need less food, so they gain weight more easily if portions stay the same. Treats, human food and food from neighbours add up, and International Cat Care says tasty, energy-dense food left out all the time can lead to overeating. Scoops and cups are also easy to overfill.

International Cat Care says less active and indoor cats are at greater risk. An illness that slows a cat, such as heart disease, lung disease or arthritis, can also lead to weight gain. If an unneutered female gains weight, your vet will rule out pregnancy.

Health risks of extra weight

International Cat Care says obesity increases the risk or progression of many diseases, including diabetes, lower urinary tract disease, constipation, skin disease and fatty liver. Extra weight also puts stress on the joints. It carries a higher anaesthetic risk too.

No evidence shows that obesity causes arthritis, but it is likely to make existing arthritis worse. Read more in our guides to diabetes and arthritis in cats.

Being overweight can also worsen breathing difficulties in cats with asthma, and PDSA says cats carrying extra weight find it much harder to stay cool. Research has shown that being obese, or too thin, can shorten a cat's lifespan.

Losing weight safely

Talk to your vet before changing your cat's food. International Cat Care says sudden food restriction can make cats ill, and some health checks may be needed first. Cats Protection says not to starve your cat or use an extreme diet that cuts food drastically in one go. Blue Cross also warns against crash diets.

The reason is serious. International Cat Care says cats that lose weight too quickly can develop hepatic lipidosis, a potentially fatal liver disease where fat builds up in the liver. The MSD Veterinary Manual (US) links this liver disease with a period of poor appetite, especially in obese cats, so an overweight cat that stops eating still needs to see a vet.

Your vet can create a plan that combines feeding, exercise and careful monitoring. Loss should be gradual and steady, and for a cat that is severely overweight it may take up to a year to reach ideal condition. Many practices run weight clinics, so ask yours.