Hi there!
My Em was diagnosed in 1999 and was prescribed w/d as well. It gave her horrible diarrhea (horrible) and we talked to the vet and they said just keep feeding her what we were feeding her. My vet was pretty lax when it comes to nutrition.
Reading up on W/D I learned the reason vets prescribe it for cats is because it works for dogs. W/D is higher in fiber, so the thought is that it will empty out of the stomach slower and help manage BGs. Again, this works for dogs - mostly because they are omnivores and not obligate carnivores like cats are.
Cats need reduced carbohydrates / fiber and increased protein. Most vets who are up to date on this prescribe D/M. This is also pretty high in carbohydrates compared to the foods you can buy at your local store. Since other people have talked nutrition I won't go down that road
IF your vet is open to new ideas, and is interested in talking to you about different food options and home testing, then stick in there with your vet. Having a constancy when it comes to vet care is important - but only so far as that you feel comfortable and aren't worried about doing something a little different then what your vet suggests.
Remember, that your vet works
for you. If at any time you feel his suggestions are orders or that you can't deviate from them, then he's abusing his power. Some vets do get a complex about how they know what is right for every situation. Most vets do not and are willing to learn with you and work with what you want to do. If you have one of those, hold onto him/her.
We would never wish diabetes on a cat, but most of us have found that because of it we are closer to our pets and that bond becomes more powerful. We've also had some great friendships formed on this board, so while you'd never wanted to be here, you'll be glad you are.
Connie