9 Possible Causes of Feline Weight Loss


Obesity is appearing in cats at epidemic levels, and we constantly hear about how we can help our feline friends lose weight. But what if your cat has the opposite problem? If your cat is losing weight and you’re not dieting her with the guidance of your veterinarian, there are a lot of reasons this could be happening. Any of them could mean your cat’s health is in jeopardy, so please don’t ignore your cat’s weight loss. Pay attention to the tips below.

Here are nine reasons your cat could be losing weight:

1. Stress

Cats are a lot like people: Some overeat or binge on junk food in response to stress, and some lose their appetite. Stress can come from environmental causes such as excessive heat or noise, emotional issues such as mourning or disharmony in the household, competing for food, or new circumstances such as a move of house

2. Nausea

Many illnesses including pancreatitis and hepatitis can cause nausea. Like people, cats aren’t thrilled to eat when they feel like they want to throw up.

3. Dental disease

If your teeth hurt, you’re not going to be very excited about eating. The same is true for cats. Gingivitis, resorptive lesions ("kitty cavities"), and broken teeth make it very difficult and painful for your cat to eat, particularly if you’re feeding dry food.

4. Nasal congestion

Scent is the primary appetite stimulant for cats, and if your cat’s nose is blocked due to an infection or allergies, she won’t smell her food and therefore won’t eat.

5. Parasites

Intestinal worms survive by stealing nutrition from the food your cat eats. A heavily worm-infested cat could lose weight because she’s not getting any energy from her meals, no matter how much she eats.

6. Constipation

When your cat’s intestines are filled with fecal matter she can’t expel, her appetite will suffer. If you haven’t seen the appropriate number of deposits in the litter box (most cats have one to two bowel movements per day), she may need some veterinary assistance to get her plumbing unclogged.

7. Chronic diarrhea

If your cat has diarrhea (and this includes "cow pie consistency” stools as well as liquid stools), food is moving so quickly through the digestive system that the body doesn’t have time to absorb nutrients. The result: weight loss.

8. Metabolic diseases

The most common hallmark of illnesses such as diabetes, hyperthyroidism and renal disease is weight loss. The biological mechanisms behind the weight loss vary from disease to disease, but any time a cat is rapidly losing weight, she should have a blood test to detect these illnesses.

9. Cancer

Cats with cancer may lose their appetite. The severe pain caused by the disease can cause your cat to lose weight. Cancer cells also steal a lot of energy for their own growth, which can cause muscle wasting and weight loss.

If you notice your cat is losing weight, take her to the vet right away. Even if the weight loss is caused by a serious illness, early detection can vastly improve your kitty’s prognosis for a full recovery.

Have you ever taken your cat to the vet just because she was losing weight? Have you been shocked when you took your cat for a checkup and found out she’d lost a significant amount of weight? What was the result of your intervention? Did I miss any potential causes of weight loss? Share your thoughts in the comments.

More on cats and eating:

Learn more about your cat with Catster:

About JaneA Kelley: Punk-rock cat mom, science nerd, animal shelter volunteer and all-around geek with a passion for bad puns, intelligent conversation, and role-play adventure games. She gratefully and gracefully accepts her status as chief cat slave for her family of feline bloggers, who have been writing their award-winning cat advice blog, Paws and Effect, since 2003.

Get Catster in your inbox!

Stay informed! Get tips and exclusive deals.

Let Catster answer all of your most baffling feline questions!

Starting at just


Follow Us

Shopping Cart