Considering I had little else to do, I flicked through my old science books, and googled it
If you crave sugar theres not really much you can do, other than try to balance out fruit with sweets. the sugar in sweets is broken down almost immediatly after you eat it and it sends your glucose levels soaring for a short while, but fructose, found in fruits, is broken down slower and keeps your glucose levels more stable, so if you reduce how much sugar you eat gradually then your glucose levels will reduce and the way fructose works, your glucose levels should stay relatively steady. this is taking into account that insulin breaks down any sugars you put in your body, be it sugar, sucrose, glucose, fructose ect.
I don't know how long it would take take, I mean glucose levels never stay exactly the same, and sometimes they can be really high and really low but I do know it took my grandad like 2 years to steady his glucose levels and he still gets hypos and stuff. and really this is all theoritical. I don't know if it would work as simply as I put it.
If you do want to reduce your glucose levels really you should speak to a doctor or dietitian coz they know more than the paragraph which is mostly notes I'd scribbled down during a lecture when I was in yr 11.
Or diabetic sweets or sugar free stuff could help =S