My Vet claims that they have changed the formula and that she has good results with it.
The ingredients in the dry are: Chicken By-Product Meal,
Barley,
Wheat Gluten, Corn Gluten Meal, Soy Protein Isolate,
Tapioca, Powdered Cellulose, Chicken Fat, Natural Flavors, Dried Chicory Root, Fish Oil, Psyllium Seed Husk, and lots of chemical vitamins and minerals. While "powdered cellulose" isn't a grain, it's one of my personal pet peeve ingredients in a lot of "prescription" foods. It used to be believed that a diabetic cat should eat a high fiber diet. Powdered cellulose is basically a fancy name for sawdust (which, I will agree, is high in fiber....but I don't want my cat eating it)
It's not that your vet is a "bad" vet or anything like that. The sad truth is that vets get very little education on diabetes in school (less than 1 day) and that covers all kinds of animals. Vet schools only have 4 years to teach everything a vet needs to know, so they just can't take the time to go into details about every different disease and every different treatment for that disease...and then in different animals on top of it! They just can't spend 2 weeks teaching everything there is to learn about diabetes in cats...then another 2 weeks on diabetes in dogs...another 2 weeks on diabetes in rabbits, etc. etc. All they can do is gloss over it. It's up to the student vet to do further research (if and when they have the time) and then when they start working, they learn some from the more experienced vets they work with (who unfortunately, also didn't get much in the way of formal education when they were in school). Yes, vets are required to get continuing education to keep up their license but they generally get to choose the courses they want to take...so if there are some CE classes for diabetes, it's usually the canine ones they're going to go to because they see a lot more diabetic dogs than cats.
They get even less education on nutrition (although this is starting to get a little better) but the problem there is that the people who fund this education are the "prescription" food manufacturers so they're going to push their own products.
There's absolutely nothing special in any of the "prescription" foods that actually requires a prescription or that treats disease. There's a big class action lawsuit here in the US against Royal Canin, Hill's and Purina over this.
To quote the FDA/CVM Communications Staff Deputy Director:
“‘Prescription diet’ is an industry-coined term and holds no legal meaning.”
In other words, these diets contain no ingredient that actually requires a prescription. The trademarked term “prescription diet” is simply a clever marketing tool between Hill’s (and other manufacturers) and veterinarians. The sale of these diets is restricted (by Hill’s, not by law) to veterinarians only. In return, Hill’s enjoys a boost in perception of quality brought about by this profession’s endorsement of their products.
This message board has been helping diabetic cat caretakers for over 25 years. The people here have the time to research for the latest information and treatments (and we do have professional researchers, biologists, chemists, etc. in our membership). We have the real life, 24/7/365 experience in what works...and what doesn't.
We can't force you to change what you feed your cat, but even if you just stop feeding the kibble, it will help. The canned Royal Canin is lower in carbs than the kibble by quite a bit! (about 12% versus about 25% for the kibble). Just tell your vet that your cat liked it at first, but now refuses to eat it. (it's also 100% guaranteed so you can get your money back).
As for using the pen versus a syringe, syringes are actually easier for most people. When you use the special pen needles, you're supposed to "prime" it each time by wasting 2 units....that's throwing 4 units per day in the trash! Also, to be sure the entire dose is given, you're supposed to hold the needle in for 10 seconds....and with those pen needles only being 4mm long, if your cat moves just a little, you could end up with them not getting the whole dose. Lastly, the pens "dial a dose" is only able to do dose changes in whole units. It doesn't sound like much, but to go from 1 unit to 2 units is a 100% increase in dose. That's like a human going from 20 units to 40 units!...there's some doses in between that should be tried!
Keep asking questions though! The best way to learn is to ask lots of questions and having several people explain it in different ways is good because one of them may explain something in a different way that makes sense to you.
No matter what, we all want what's best for you and your "extra sweet" Toby!!