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Why is my Cat Losing Weight?

orange tabby cat

Written by Dr. Sam Parker, DVM

So, you noticed that your cat is losing weight and seeming slimmer or lighter on your lap. From food type, dental health, a medical condition, even bowl placement, there are a lot of reasons why your cat is losing weight. Let’s break down some reasons why to get your cat back on the right track.  

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Reasons Your Cat is Losing Weight

cat eating from a bowl

Let’s start with cat food and food placement. First, did you recently change cat food? Or did you start changing volumes of food offered? Did you move your cat’s food bowl? Does it seem like your cat can find the food and chew it?

My Cat is Losing Weight but Eating Well

If your cat is eating normally and none of these things are happening, it could be a medical reason why your cat is losing weight. Here are some of the most common medical reasons why your cat could be losing weight.

Hyperthyroidism in Cats

Sometimes as cats age they can get abnormal thyroid tissue which cause an over production in thyroid hormone expediting metabolism.  Cats who still eat ravenously but are losing weight may have hyperthyroidism.  A blood test to check the thyroid levels can help determine if this is the cause.

Diabetes in Cats

cat being pet

Cats who are overweight for a majority of their lives often start to lose weight suddenly as they age. These cats seem to still eat fairly regularly and in normal amounts. 

A way to tell if your cat is diabetic is you may see them standing in a “plantigrade stance,” or down on their hocks where their hind limbs are positioned at a flatter angle. 

Make an appointment with Hello Ralphie. Vets available 7 days a week.

Cats with Intestinal Disease

Lymphoma or irritable bowel disease may cause ongoing vomiting or diarrhea on an occasional or consistent basis. There also may be changes in appetite or generalized picky behavior.  This often requires first a gastrointestinal blood profile run while fasted, then an intestinal ultrasound to check the thickness of the walls of the intestine. 

In order to determine if it is lymphoma or IBD, fill thickness biopsies need to be performed. Chemotherapy or steroid therapy can be used to manage the condition. Often steroids are started to help treat without knowing which of these two diseases it is.

cat stretching

Cats with Dental Disease

If you notice your cat chewing on only one side or has difficulty apprehending food it could mean that dental disease or stomatitis is causing eating to become painful. A veterinarian can look at your pet’s teeth and make an assessment to see if there is a need for a dental procedure. Routine dental care is important in pets to prevent getting to this point. Medications or a tooth extraction may be needed.


By Dr. Parker

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  1. […] Other clinical signs of potential intestinal worm infections include abdominal bloat, increased hunger that doesn’t translate to weight gain, and abnormal lethargy. Read “Why is my cat losing weight?” here. […]

  2. […] Other signs that your cat may be developing disease include increased vocalization, rapid weight and muscle loss, increased thirst and urination, or excessive hunger without weight gain. In any of these are noted, it’s recommended to speak with a veterinarian. Does your cat appear to be losing weight? Read about possible reasons from a Hello Ralphie vet. […]

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