Why is my cat so skinny and not gaining weight even though he eats?

Since Fred is an older kitty it is likely he is suffering from an overactive thyroid. Kidney disease and diabetes can also cause this. I suggest you take him to your vet for an exam and a blood test. Hyperthyroidism is easily treated with thyreostatic medicine and is likely the most common cause for the weight loss.

Cats can be thin for a variety of reasons. Make sure he has been checked for parasites or dewormed recently. Some cats will also become thin due to kidney disease or hyperthyroidism. Sometimes this can happen even before kidney disease begins. Any GI disease will also cause a thin body. Lastly, some cats have a fast metabolism. Make sure Choo Choo's bloodwork is all normal and that parasites are not a concern. Then you may try focusing on nutrition. I recommend the brand Royal Canin. It's diets are all tested and formulated to contain appropriate protein levels that are high quality and easy to digest. Feed one of the higher calorie diets available. This may help to put weight on him. You can also supplement with a high calorie canned like A/D or R/S.

Significant weight loss is always a concern, especially if his appetite is good. Hormonal conditions such as diabetes and thyroid disease or poor absorption and digestion of his food is possible and I would recommend a full physical and blood panel as soon as possible in order to stabilise his condition before he becomes too frail

Weight loss coupled with a normal or increased appetite can be a sign of diabetes or hyperthyroidism, to name a couple of possibilities. I recommend getting Felix seen by your vet as soon as possible for an exam and labwork to determine the reason for his weight loss and get him started on treatment.

Poor Canelo. I am sorry that it has been difficult to get him to gain weight. With him being young and petite and intact then I would not be too concerned. Of course, without doing an exam I cannot say this for sure. If he is really skinny and all of his bones are showing then yes, I would be more concerned. If his bones are not showing and you cannot see his ribs then I would be less concerned. Some cats are more petit and slender especially if they are very active and outdoors. I would also recommend to have him neutered as that may also help him gain weight. Finally, if he is really skinny and you are able to see his bones, I would recommend to ensure your vet tested his thyroid (high thyroid isn't common is young cats but possible). Then I would recommend to increase the amount of food you are feeding and if he is still not gaining weigh then the next step would be abdominal x-rays or ultrasound. I hope this helps some. I would love to talk to you more on the forum or if you would like to set up a consult.

I would recommend taking Oliver Paul into for an exam by a veterinarian. They can do a full exam, and a geriatric blood work panel. They may also take his blood pressure. High blood pressure can cause weight loss in older kitties. It can also cause eye problems. Another common and treatable condition in older kitties is hyperthyroidism. They get benign (non-cancerous) tumors on their thyroid gland that causes them to produce too much hormone which up regulates their metabolism. They will eat a lot and continue to drop weight. A veterinarian can get Oliver on a plan to recovery! Thanks for reaching out to Petco Pet Education Center, formerly Petcoach!

When an senior cat is eating more frequently yet losing weight, this can be a sign of hyperthyroidism. With hyperthyroidism, the thyroid gland is secreting too much hormone which causes an increase in the pets metabolism and subsequent weight loss. Have your vet check Hopes T4 levels to see if she is hyperthyroid and in need of medication to help stabilize her hormones so that she doesn't continue to waste away. This is easily diagnosed and treated with medication (i.e. Methimazole). Your vet will also want to run baseline bloodwork on your pet to make sure no other disease processes are there.