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My cat is losing weight but still eating. Is his new food to blame?

Updated on September 23rd, 2025

Pet's info: Cat | American Shorthair | Male | neutered | 1 year and 11 months old | 10 lbs

My cat Tigger will soon be turning 2 in March. He's an orange tabby. I noticed over the past month that he is getting skinnier. He is eating his wet food twice a day. I leave dry food out all day. He doesn't seem to be in any pain. He purrs a lot and loves to be held. Only thing that has changed is I switched the dry food from a mixture of kitten and indoor formula to just indoor formula because our other 3 cats are a year old now.

1 Answer

Most Helpful Answer

Elva Ma DVM

Answered By Elva Ma DVM

Veterinarian

Published on February 13th, 2018

Hello, and thank you for your question. I can see from the photos that he has lost weight quickly (when this occurs, they lose weight first from the back). Some possible causes include inflammatory bowel disease, or intestinal parasites, which may also show concurrent signs of vomiting or diarrhea.

I would start by offering his old diet again, if only because the kitten formula has a higher fat content which may help him gain weight. But if the new diet has a new ingredient that he is allergic to, then going back to his old diet may really help.

If Tigger is not gaining any weight back within a week, I would recommend taking him to the vet. They can perform a stool test to rule out intestinal worms, and may recommend blood tests to rule out inflammatory bowel disease. A hypoallergenic diet trial may also be recommended. Supportive medication may also be prescribed if diarrhea or vomiting is also present.

I hope this helps, and that Tigger feels better soon!
Vote Icon1Pet Parents found this answer helpful

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