It can be hard to know whether or not your cat is too skinny. According to International Cat Care, 39 to 52 percent of U.K. cats are overweight. Because so many of the cats we see are overweight, a normal weight may seem abnormally thin to their pet parents. It can also be hard to tell whether your cat is skinny if they have long hair or a sagging belly.

While a skinny cat isn't necessarily a cause for an emergency trip to the veterinarian, if you find yourself searching "How to put weight on a cat," then it's probably time for further investigation.

Is My Cat Too Skinny?

Knowing whether your cat is too skinny can be challenging.Fortunately, there are two easy tools you can use to determine if your cat is too thin, overweight or just right.

• The Body Condition Score: Vets use the body condition score (comparable to body mass index for humans) to evaluate a pet's weight. A body condition score chart can help you determine if your cat is too skinny. You can either find a guide online, from organisations like the PDSA, or at your vet's office.
• The Hand Test: You can also use your hand as a reference to determine your cat's body condition. Feel your cat's ribs (located behind their front legs); if they feel like the back of your hand, then their weight is just right. If their ribs look or feel like your knuckles, then you have a skinny cat. If the ribs feel like your palm, then they're likely overweight. Still not sure? Check out this video from dvm360 that demonstrates the hand test.

Causes of Weight Loss in a Skinny Cat

There are two main causes for a skinny cat: either they’re not eating enough, or they're expending more calories than they’re taking in. They may not be eating enough due to stress, dental disease, nausea or a host of other reasons. Cats with certain diseases can experience weight loss and this can be the first, and sometimes the only, outward sign that an underlying disorder has developed. Weight loss can also be due to age-related changes in body function and metabolism that can occur in some geriatric cats over 10 years of age.

The other reason that a cat might be too skinny is a lack of access to food. If you find a stray cat that is malnourished, you can contact your local shelter or veterinarian to get their opinion on what to do to bring the cat back to a state of health. They may direct you to bring them in if possible. Adopted stray cats should always be taken to the veterinarian to screen for health problems.

Weight loss can be subtle and slow in onset. Recent research has shown that weight loss is a very early sign of kidney disease and may start manifesting itself three years before a diagnosis is made. Early intervention provides the opportunity to begin therapies earlier. Therefore, regular checkups with your veterinarian that include body weight can be very helpful in the early detection of the disease.

It is considered a medical emergency if your cat (skinny or not) stops eating altogether. If that's the case, you should take your cat to the vet right away. Cats that don't eat for days on end can develop a life-threatening condition called hepatic lipidosis, also known as fatty liver syndrome.