My 9-year-old cat is losing weight but still eating and drinking. Why?

I am sorry to hear about Sugar. My rule of thumb is that any cat who is losing weight needs to be seen by a vet sooner rather than later. I am particularly worried about kidney disease which is common in older cats. After a good physical exam, your vet may recommend bloodwork to check on the kidneys and thyroid in particular. Best of luck to you and Sugar!

My concern with Menie is that he can have one of a few different things going on. As cats age they can become diabetic, have chronic kidney disease or even become hyperthyroid. With all these diseases you will see an increase in drinking and weight loss. I would recommend taking Menie to the veterinarian and having blood work and a urinalysis performed to see exactly what is going on with him. The urine will also show if there is a urinary tract infection, which they can have if they have diabetics, kidney disease or even if they don't have another disease going on. I hope Menie feels better soon and thank you for using Petco Pet Education Center, formerly Petcoach.

It is fairly rare, but ask your veterinarian if your kitty may be suffering from Cushing's disease or liver disease. Also sometimes cats can still be hyperthyroid, even though the thyroid parameters are within normal limits (this is called euthyroid sick). He could also have a tumor. In any case, this needs to be investigated further.

Cats that are losing protein through their kidneys can lose weight. With your cat's medical history, I would recommend having him examined by the vet. Blood work will check the kidneys and urinalysis will look for extra protein in the urine. The blood work can also screen for other issues that can cause weight loss.

In an older cat, my first thought would be dental disease. This would be painful for Krinkle, cause him to eat less, and subsequent weight loss. It could also be that he has diabetes, kidney failure, or hyperthyroidism. Having him seen by a vet this week is a good idea. I hope this helps!

These are indeed an unusual set of symptoms, thyroid disease and diabetes would be the first suspects for a cat with increasing appetite and weight loss. A specialist ultrasound scan of the abdomen may be worth while to investigate difficulties with food digestion and absorption or even tumours using up the calories

I definitely think you should have Dahlia examined by your veterinarian. A few diseases that could cause an increased appetite with weight loss include intestinal parasites, diabetes, and hyperthyroidism. Your vet can examine Dahlia and her stool, and may recommend checking lab work if parasites seem unlikely. All of these diseases are very treatable, but it's important to get a diagnosis quickly.