Reddit mentions of Your Cat: Simple New Secrets to a Longer, Stronger Life

I'm not currently a cat owner, but I've read a lot about cat nutrition. First, a lot of vets make their food recs based on what manufacturers say. If your cat is a kibbletarian, odds are the food you are feeding is too high in carbs because it's cheaper to produce than meat. Cats don't need rice, corn, or any grains, and too much can lead to feline diabetes. Even some of the "scientific" formulations have problems. I know it can be frustrating when you are doing everything "right" but it doesn't seem to work. You might want to check out this webiste or this book for more information on cat nutrition. You might have a great vet, but not all specialize in cats. I grew up on a farm, and our vet was great with cattle, but he wouldn't be my first choice for dealing with specialized cat problems. It's obvious you care about your cat, and I wish you the best of luck :)