Unexplained Weight Loss in Cats: What It Could Mean

8 min read
8 min read

Updated - Aug 17th, 2022

Cats have a reputation for lounging around and eating too much – due in part to a famous lasagna-loving tabby named Garfield.

While Garfield may be a fictional character, there are plenty of overweight cats in real life. You’ll see a lot of advice out there for pet parents who are trying to help their kitty shed a few extra pounds, but what about cats that have the opposite problem?

If your cat is experiencing unexplained weight loss, we’re here to help!

A number of factors can contribute to unhealthy cat weight loss – From parasites like intestinal worms to underlying health issues like hyperthyroidism to something as simple as not being able to reach their food bowl. In any case, veterinary attention is extremely important, not only for getting your cat the right treatment but for detecting the cause early.


The most obvious symptom of weight loss in cats is noticing your furry friend getting skinnier and skinnier. It’s unlikely that you’re weighing your cat regularly unless they’ve struggled with obesity in the past – in which case, weight loss might be what you want. If you’re intentionally restricting your cat’s food intake (under a vet’s orders, of course) to reach an ideal weight, it’s possible that your cat is shedding pounds in a healthy way and there’s no cause for concern. 

Unhealthy weight loss, on the other hand, may be harder to notice. We often don’t always catch subtle changes in our beloved felines, and some of us don’t even know our cat’s body weight to begin with!

If your normally healthy cat starts looking gaunt, that’s probably a bad sign. Drastic weight loss in a very short span of time is almost certainly a sign of a potentially health issue. This is dangerous and can cause other health complications as the body is forced to depend on fat stores for energy.

There are certain home tests you can perform to determine whether your cat is losing a concerning amount of weight. Rub your cat on the back and sides. You should be able to feel their ribs under a layer of fat. If their ribs are visible, they’re underweight. Looking from above, you should notice a tuck at the cat’s waist which is visible but not extreme. Take note of your cat’s eating habits, too, and make sure they’re being properly nourished on a regular basis.


There are numerous potential causes of weight loss in cats. The obvious reason is simply that your cat isn’t eating enough. This may be the result of obstacles in your home: 

  • If your cat is old or has developed a condition like osteoarthritis, they may not be able to reach a food bowl set on a high platform. 
  • If you have another pet, it’s possible they’re nibbling away at the food you’ve set out for their friend. 
  • The food you’re serving might lack appropriate nutritional value, or your cat could be responding badly to it. 
  • Stress and depression may also be affecting your cat’s appetite.

Many times, weight loss can be a result of underlying diseases. These diseases might be more serious and require veterinary attention. But this also presents a way forward, as treating these diseases can help stop weight loss and set your cat on the road to recovery. These diseases may include:

  • Intestinal parasites, especially if your cat is often outdoors
  • Feline diabetes (diabetes mellitus)
  • Feline hyperthyroidism, caused by a benign tumor on the thyroid gland
  • Viruses like FIP, FeLV, and FIV
  • Kidney disease
  • Forms of cancer
  • Gastrointestinal problems
  • Organ failure, especially in older cats
  • Dental problems


  • Use the home tests described above: rub your cat to feel for exposed ribs, observe from above to make sure they have a healthy body shape, and take note of eating habits.
  • In order to diagnose underlying conditions, your veterinarian may perform additional tests, including blood work, urinalysis, and a physical exam.
  • If your vet suspects parasites as the cause of your cat’s weight loss, they might perform a fecal exam.


Treatment is highly specific to your cat’s condition and will depend on the underlying cause of weight loss. There’s no one solution for getting your cat to a healthy weight, especially since your cat may not be able to control the amount of food they’re able to eat or digest. However, your veterinarian may prescribe one of the following treatment plans:

  • Thyroid medication
  • Dewormer medication to take care of parasites
  • Changes to your cat’s diet: for example, switching to more nutritious or easily digestible foods, from wet to dry food, and avoiding foods that may be causing an allergic reaction
  • Appetite-stimulating medications or feeding tubes in extreme cases of anorexia
  • Teeth cleaning and dental work
  • Removing stressors, like loud noises, which may be causing behavioral difficulties leading to a decreased appetite

Recovery and care

After any underlying causes have been treated, you should be mindful about what your cat is eating and how much they’re eating. Make sure your cat’s bowl is in an easily accessible place. Give them food that’s easy to digest and high in caloric content – while making sure that you aren’t overfeeding them and causing them to pack on excess weight.

It’s extremely important that you keep your cat well-nourished. If they aren’t getting replacement calories each day, they can begin to suffer from a condition called hepatic lipidosis, or fatty liver disease, as their body stores large amounts of fat in the liver to provide a source of energy. Increased liver fat can cause liver failure, which is potentially fatal. To ensure your kitty’s body doesn’t start working against them, it’s essential to keep them well-fed. 

If chronic kidney disease is the cause of your cat’s weight loss, long-term care to mitigate symptoms is the only way forward. Modify your cat’s diet to restrict intake of high-protein foods and promote the consumption of water, fiber, and antioxidants. Monitor your cat to make sure they’re actually eating the foods you give them during this transition. In the case of feline hyperthyroidism, a diet limited in iodine may be the best way forward, in addition to surgery and medication. 


Because there are so many potential causes of weight loss, it’s difficult to pinpoint a strategy for making sure your cat maintains a healthy weight.

Regular screening is one of the easiest methods for preventing some of the underlying diseases that can cause weight loss in cats. Regular vet checkups can help you identify potentially serious health conditions before they begin to have dangerous consequences. Feline wellness is all about preparedness! Since our kitties can’t speak for themselves, it’s up to us to be proactive in monitoring their well-being.

What to expect at the vet’s office

As always, keep notes of your cat’s symptoms and be prepared to discuss their medical history. Discussing previous ailments can help to narrow your veterinarian’s focus and help them identify the most likely cause of your cat’s weight loss. Your vet will likely conduct a few tests, including blood work and urinalysis to rule out chronic kidney disease and stool samples to identify parasites. They may also ask you about behavioral issues since stress and depression can also lead to cat weight loss.

The bottom line

Feline weight loss can indicate serious underlying health concerns such as chronic kidney disease, cancer, hyperthyroidism, and viruses to name a few. If your cat is suffering from these, their weight loss may only be a symptom and not the full picture. That’s why it’s crucial to monitor your cat’s food intake and look for fluctuations in their weight. If you notice sudden and drastic weight loss, take your cat to a vet to address their symptoms and rule out any serious medical conditions.


Does pet insurance cover treatment for cat weight loss?

Your pet insurance plan may cover treatment if your cat’s weight loss is the result of an illness or injury that arose after your coverage began. If it’s the result of an underlying condition, it may not be covered unless it meets certain criteria. In other words, like most things related to unhealthy cat weight loss, it depends on what is causing the condition.

Is all weight loss bad?

If you’re instructed by your vet to help your cat lose the excess weight, the weight loss may actually be what your cat needs. In this instance, reducing caloric intake or increasing exercise can be better for them. However, sudden and uncontrollable weight loss is not healthy, and is most commonly a sign of an underlying problem.

How can I increase my cat’s caloric intake?

One step is simply to make it easier for them to reach their food bowl. Don’t put their bowl on an elevated surface, particularly if you have an older cat whose limbs might not be as spry as they used to be. Even something as seemingly insignificant as the position of the bowl might have an impact. Cats are finicky creatures, and they’re very sensitive to their environment. Making sure they’re comfortable in the space you’ve provided is one of the easiest things you can do.

How will the vet know what’s causing my cat’s weight loss?

Your vet will likely conduct multiple tests depending on what they suspect the cause to be, including blood work and urinalysis. You should be prepared to discuss your cat’s medical history to help narrow down the cause of your cat’s weight loss, since not everything is apparent from visual or physical examinations.  

Did you know

  • The healthy weight for an adult cat is around ten pounds, but this varies by breed.
  • Protein is generally a good thing for cats – after all, they’re carnivores – but if they have chronic kidney disease, a high-protein diet can be dangerous.
  • Pumpkin Pet Insurance plans offer 90% cash back for covered veterinary bills. Learn more about how a Pumpkin plan can help your cat stay happy and healthy.

George Menz

George is a copywriter who has lived alongside cats his entire life.
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