Just like humans, cats can be naturally thin. Cats come in all different body types, and some breeds are skinnier than others.

However, it is possible for your cat to be too skinny – sometimes weight loss happens as a result of health problems.

If you think your cat is too skinny, it’s important to seek professional care to help get them back on track. In this article, we’ll talk about effectively assessing your cat’s weight, as well as how to tell if your cat is too skinny.

What is an optimal weight for a cat?

Why is my cat so skinny

There’s no one ‘right weight’ for your cat – some cats are just built to be larger than others. Cats can vary in size from 5 pounds to 25 pounds, depending on their build. Cat body types vary on a scale from Oriental to Cobby.

Maine Coons are a great example of a Cobby breed, while Siamese cats are a great example of an Oriental breed. Generally, you should be able to easily feel your cat’s ribs, spine, and pelvis, but not see them.

Signs Your Cat is Underweight

It’s important to monitor your cat’s weight, as it can be indicative of health problems. The best way to tell if your cat is underweight is to use a body condition scoring tool. Let’s look at some of the things you might notice when looking at your cat’s body condition score (BCS).

If you notice any of these signs, it’s important to take your cat to see a vet right away to determine the cause of their weight loss.

Visible Spine, Ribs, and Shoulder Blades

Why is my cat so skinny

The most visible sign that your cat is underweight is if their spine, ribs, and shoulder blades are all visible through their fur. While the skeletal structure can be very prominent in some Oriental breeds, you shouldn’t be able to see the definition of their individual ribs, spine, or shoulder blades.

Lack of Fat On Torso

If your cat has long hair, it can be difficult to tell how skinny they actually are. In this case, you should get in the habit of checking your cat’s weight regularly, just to make sure they are healthy.

Cats should naturally have some fat and muscle hiding their bones, so if they feel particularly bony, it could be an indication that they are underweight.

cat so skinny

Narrow Waist

While cats vary in size and shape, if you notice that their waist is disproportionately narrow, they could be underweight. This is particularly worrisome if your cat used to be larger and has been losing weight.

Causes of Weight Loss in Cats

There are a number of reasons why your cat might be losing weight.

If you notice that your cat is underweight, it is important to take them to the vet as soon as possible to determine the underlying cause.

This is crucial for preventing long-term health damage and getting your cat back to their optimal weight as soon as possible.

Here are some of the most common causes of weight loss in cats.

Kidney disease

Around 1 in 3 cats will suffer with chronic kidney disease (renal failure), which will often cause weight loss and loss of muscle. Cats with kidney disease will often be drinking more and peeing more, too.


Diabetes affects your cat’s ability to process food, causing them to drop weight quickly. Like renal disease, diabetes is accompanied by an increase in appetite, and a high water intake.


Cats can develop cancer as they get older, which affects their appetite. Cats who have cancer may have other signs, depending on the type of cancer they are suffering with.

Why is my cat so skinny

Gastrointestinal Problems

There are a number of digestive issues that can cause your cat to lose weight. If your cat is having trouble digesting, they won’t want to eat and can end up underweight. Pancreatitis, IBD, allergies, and other causes of diarrhea in cats can result in weight loss.


Just like humans, cats can develop thyroid issues. Hyperthyroidism causes an increase in your cat’s metabolic rate, meaning they burn calories too quickly. These cats are often hyperactive and hungry, but lose weight rapidly. You may also notice other  digestive issues, like vomiting and diarrhea.


It’s unusual for adult cats to develop parasites that are severe enough to cause weight loss, but it’s certainly the case in kittens, or in cats that have been living rough. Ask your vet whether worming your cat might make a difference.

Tooth Problems

Why is my cat so skinny

If your kitty’s teeth are hurting, she’s likely not going to want to eat. There are a number of feline dental issues that can contribute to weight loss, including problems with the teeth and gums.


Cats can develop anxiety or depression if they aren’t comfortable in their environment.

This can lead to food avoidance and eventual weight loss.

How to Help Your Cat Gain Weight

Your vet will provide you with specific instructions to help your cat gain weight, which you should follow as closely as possible. If your cat is dealing with a specific medical condition, they will likely prescribe a form of medication to treat the underlying problem.

Don’t forget that far more cats are overweight than underweight, so you need to be absolutely sure that your cat is underweight before you try to get them to gain weight.

At home, the best way to help your cat gain weight is to make sure they have food that is easily accessible to them.

This may mean placing it somewhere that doesn’t require jumping or bending over. You should also make sure your cat enjoys their food – try switching to another brand if they are finicky.

While some cats are naturally skinny, extreme thinness could be an indication of underlying health issues. You should always take your cat to the vet if they are underweight – the faster you can get them treatment, the sooner they’ll be happy and healthy again.