For the love of your pets: Pet's unexplained weight loss could indicate health problems

Oct. 14, 2010 at 5:14 a.m.

By John Beck

My cat eats and eats and eats, but never seems to put on any weight. In fact, it seems like she is losing weight. She is an indoor cat and her daily activity hasn't changed. She still sits on the couch, back by the window most of the day. She doesn't seem to drink any more water than normal and her litter box habits appear to be the same, with the exception of more feces. Is there anything wrong with her, or is this normal for cats as they get older?

Weight loss, while maintaining a good appetite, isn't normal for a cat. Especially if your cat appears to be eating more than normal and is still losing weight. Usually, as cats get older, they will lose a little weight, but this weight loss is similar to humans as they age.

The first thing to consider is parasites. When was the last time your cat was dewormed? Do you have her on heartworm preventative? Even though your cat is indoors, they can still suffer from internal parasites or heartworms. If you or anyone else tracts even trace amounts of an infected animals feces inside the house, your cat could get intestinal parasites, like hookworms or roundworms.

It is always a good idea to deworm your cat at least once a year during her annual visit. If you have ever been bit by a mosquito while sitting on your couch or lying in your bed, then your cat has probably experienced the same. The mosquito bite is what can infect your pet with heartworms. If both of these problems are ruled out during the exam, a monthly preventative can be used to prevent future infection.

A few blood tests and urinalysis can rule out the next four major causes of weight loss in aging cats. Hyperthyroidism (an overactive thyroid gland) can cause your cat's metabolism to shoot through the roof. This causes a cat to burn more calories than the average cat, even when sitting perfectly still. Second could be diabetes. Sugar diabetes can sometimes cause weight loss due to the body's inability to handle carbohydrates and glucose properly before excreting them. Kidney disease is another cause of weight loss. When a blood panel is run and kidney values return higher than normal, we know the body is working overtime to do its job. Finally, a urinalysis can also help determine the function of the kidneys along with verifying/eliminating the suspicion of a kidney or urinary tract infection. If any of these tests are conclusive, your cat will be prescribed medications to treat the problem. After being on the medications for a couple of weeks, there should be a significant improvement.

There are a lot of reasons that your cat might be losing weight. The best thing to do is to contact me or your current veterinarian to have her looked at and a few tests run. Most veterinarians can run these tests in the office and have an answer for you within the time of a normal visit.

Dr. John Beck has a veterinary practice at Hillcrest Animal Hospital in Victoria. Submit questions to Dr. Beck at



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