Thin Cat Not Gaining Weight

I have an outdoor cat that seems pretty thin (you can feel his ribs). I feed her often. He always seems hungry and eats, but does not gain weight. Any thoughts as to why?

Thanks!


ANSWER

Hyperthyroidism can cause this, as can intestinal parasites, irritable bowel syndrome, cancer, etc. It doesn't have to be an illness, however. Sometimes an outdoor cat that is not neutered stays thin due to hormones and metabolism and exercise. To be certain, you would need a vet exam.

Thank you for writing,
Dr. Neely