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My cat is overweight. Why is he gaining weight despite eating less?

Updated On September 23rd, 2025

Pet's info: Cat | Mixed Breed | Male | neutered | 1 year and 7 months old | 12.2 lbs

My cat is probably a coupple pounds overweight according to our vet. However, I just looked up the suggested serving size (for indoor cats) for the specific cat food he is eating and he’s eating less that he should if he was two pounds lighter (the weight he should be). I know hypothyroidism is rare in cats though. Why would my cat be getting fat still?

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1 Answer

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Answered By Jeffrey Milner

Veterinarian

Published on October 21st, 2017

The first thing I would ask myself in these sorts of situations is if there is ANY POSSIBLE WAY he is getting food from any other sources. This can include other people, hunting, scavenging on the ground, the garbage, etc etc. If this is not possible, then he may just have a slower metabolism that a cat normally would for this young of an age. You are right in saying that hypothyroidism is rare in cats, to the point where I have not really ever met someone who has diagnosed this without the help of a surgical complication. There are other metabolic disorders and organ dysfunction that can result in weight gain, all of which would require further investigating with your regular veterinarian or through an internal medicine specialist. Hope this makes sense.

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