OK..first, no matter what you feed,
any food can bring the numbers up, so it doesn't matter if you fed low carb, medium carb or high carb earlier...he should go up (and he did...to 53) If you feed a medium or high carb food, the numbers will go up higher than if you feed low carb
The reason we tell you to go to a low carb food is so the insulin doesn't have to work so hard to get him into normal numbers. If you had continued to feed high carb food, he'd probably continue to need more and more insulin to combat it and get him into normal numbers. We don't want to keep feeding high carb food because it makes it even harder to get them controlled.
Continuing to feed high carb foods to a diabetic is like trying to put a fire out by pouring gasoline on it...You're adding fuel to the fire instead of suppressing it.
Cats have the unique ability to have their pancreas heal and start producing insulin again. The more time you can keep him in "normal numbers" (50-120) the more time his pancreas is healing. The idea is to lower the carbs so there's not so much to work against, and then get them "tightly regulated" (in normal numbers as much as possible) so their pancreas can heal....and gradually, as it heals, it can start producing insulin again and you can start reducing the shots until you don't need them anymore.
Not all cats will be able to go OTJ (Off the juice) but the best chance he has is to keep him in those healing numbers.
It's important that they eat because if they don't and you shoot insulin, it has nothing to "work against", and they can go too low. That's why we say to test/feed/shoot in that order so you can make sure he's eating normally before giving a shot.
In the morning, if he's above 200, I'd go ahead and give him 1 unit and then test as much as possible to fill in some of the blanks on your spreadsheet. Look at your spreadsheet like a puzzle....if the only pieces you have filled in are the edges, you can't really tell what the picture is!
If he's below 200, I'd stall,
Don't feed, and re-test in 20 minutes...Use that time to post here and ask for help. Make sure your subject line says something like "STALLING, PLEASE HELP!" so it gets people's attention.
If nobody can get to you soon enough and the next test is higher than the first one, you can probably go ahead and shoot the 1 unit because he's going up
as long as you can test later in the cycle. It's always going to be safer to skip if you can't test later in the cycle and you don't know how your cat responds to feeding and insulin.
Here's our Sticky on
Shooting and Handling Low numbers. It can also help to guide you if nobody is online when you need them (but usually, there's someone around)
The first few times people shoot under 200, we like to have someone who's got some experience watching over you.
Dose that help answer your questions? If not, please feel free to ask more! That's what everyone is here for!