? how long for numbers change

so hes been testing in the high 270-290 range and ive switched to the better lower carb foods.how long before i should start to see the difference?and how worried should i be at these numbers?he used to be 500 plus and then went in to remission with just pulling dry food and insulin.then his numbers dropped below 100 and vet said just wet food and no insulin and it worked for awhile and now just did a retest and he was almost 300.

 

When was he diagnosed? How long was he in remission? When did you start insulin again? What are you feeding?

 

diagnosed 2 years ago.took off dry food and started insulin.within months numbers dropped to under 100 and just went to wet food and he held 150-200 so we left it.we check once in a while and for some reason hes 275-300 this time so our first step is better wet food rather then whatever.insulin worked but it dropped him fast and quick so kinda rather not use if i possible.he was even on only 1 shot a day and it was very little

 

What wet food are you giving him, (not all wet food is diabetic friendly)?
What insulin are you giving him?
How much did you gave him, even a drop can some times make a difference in cats?

Cats do get out of remission for a lot of reasons and 150-200 is a little high for remission

 

Are those readings with a human or pet meter.