The best diet for a pet that is diagnosed with diabetes is a diet low in carbohydrates and high in protein. For cats it should be meat-based protein and not plant-based protein. Cats do best on this diet because they are obligate carnivores and can get all of their nutrient needs from just eating protein. Cats in the wild rarely eat any plant food and subsist solely on the other creatures they manage to catch. The other thing that feral cats have over domesticated cats is exercise as they hunt for their food and their prowess at stalking directly relates to how well they eat.
Some domesticated cats on the other hand get almost no exercise and are basically home-bound and never get outdoors for anything. Poor diet and lack of exercise both contribute to the onset of diabetes and like humans lifestyle has a lot to do with it. Overweight cats, which little exercise are prime candidates for high blood sugar problems as their diet contributes to excess glucose in the blood and a sedentary life never helps burn any of that glucose as fuel for muscles.
Cats can be treated with insulin injections to reverse diabetes and most veterinarians use a form of U 40 insulin and recommend using the corresponding U40 insulin syringes. Using matching U 40 syringes and insulin makes getting the proper dose injected much easier and one less thing tom worry about in treating your pet.
Many dogs have these same issues and often mimic their owners in obesity and poor health problems. Dogs which are spoiled by eating table scraps are eating food that will propel their blood sugar levels to extreme highs and over time will result in a chronic high blood sugar problem.
Both cats and dogs exhibit excessive drinking and urination as a symptom of diabetes and can quickly get other health problems if this is not addressed in a timely manner. Using U40 syringes and insulin to treat pets is one way to over come this, but changing to a diet best suited for the animal and increasing their exercise is a better way.