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Why is my active 10-month-old cat underweight despite eating a lot?

Updated on September 23rd, 2025

Pet's info: Cat | American Shorthair | Male | unneutered | 10 months and 11 days old | 5 lbs

I took cabelo to the vet and she said he was underweight he is 5lbs and 10 months old we tried putting weight on him but he won't gain any he is very active, and eats a lot. We had him tested for alot of different things the vet dewormed him just in case and tested his stool everything came back fine, we just don't know why he won't gain any weight he has been an outdoor cat since he was 2 months old because when inside he goes crazy begins biting and scratchin until he is outside.

1 Answer

Most Helpful Answer

Answered By Megan, DVM, CVA

Veterinarian

Published on June 12th, 2017

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.

1Pet Parents found this answer helpful

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