Often times it is - by the vets who initially see these kitties - but then after a bit - weight and everything else seems to get tossed out the window as time passes and your home testing determine what your cat needs in the way of insulin and food for that matter. If you're feeding a low carb wet food typically that's a much better food than any kind of dry food.
The issue is that when kitty is not getting the right amount of insulin, they can have a hard time absorbing the nutrients from the food their eating - and many times will lose weight - if not treated a cat can literally starve to death right in front of your eyes - all the while eating everything in sight. So it's important to get to the right dose - of course - that's what we're all trying to do - and then offer multiple small meals to support that level of nutrition that is needed just to get through the day and night too - to feel satisfied and also to help regulate those blood sugars.
Imagine in a human diabetic - being told to only eat twice a day? How miserable a life would that be - and often human diabetics are given the same advice - multiple small meals of high quality foods - a nice balanced meal - but sometimes human diabetics go too long without eating and require a candy or juice to get that roller coaster blood sugar back up to a suitable level - otherwise they'll pass out and then there are other issues...
So it's really best to feed multiple small meals all throughout the day - divide up the can into portions and then let's hope to see that once you find just the right dose those numbers will look better soon. But don't worry - Luci and I have been looking for that perfect combination for over three years - sometimes she has good days and sometimes not so good...
These are the early days for Bear so you've got an excellent shot at remission - just gotta keep increasing on a regular basis (follow your dosing method) and you'll soon start to see results