Hi and welcome to the forum.
When you say Rascal is borderline diabetic, what tests did the vet do to say this?
Do you have any tests you can share with us?
How often is he being monitored to check his blood glucose to see if it is either going back to normal with the food change or is going up?
Do you know what his blood glucose has been when checked?
If he is losing weight dispite being fed a low carb high protein diet, I do wonder if he in fact needs insulin.
Untreated Diabetic cats cannot absorb all the nutrients in the food and they are frequently hungry and thin.
What is glucose support diabetic food? Do you mean the Hills MD? And is it wet or dry?
We recommend you feed a low carb high protein wet diet. There is no need to feed a prescription food as they are all too high in carbs and cats often won’t eat them.
Here is a
food list for you. Look for foods that are 10% carbs or less. Fancy feast pates are fine.
However I would urge you to find out more about what the vet thinks is ‘borderline diabetes’
From our experience, that can mean the cat actually needs insulin. And it is not safe to leave a cat who needs insulin without it. They will sooner or later develop ketones and can become very sick.