Glucose Intolerance is probably a precursor to true diabetes. At this stage it is sometimes possible to put the condition into remission, which can be permanent. Doctors can do this by prescribing Insulin and giving the beta cells a "break" and time to recover. Patients can help by going on a severly reduced carbohydrate eating plan. I'd suggest you talk it over with your doctor and in the meantime, read Dr. Richard Bernstein's complete diabetes solution. You'll find the answers to all your questions.
If your doctor isn't a diabetes expert, you might find it helpful to get an appointment with the local diabetes consultant Some GP practices have one partner who has a particular interest in diabetes. that's the one you want.
If anyone tells you to base your meals around complex carbohydrates, to 50% or 60% of your calories. DON'T!! That's the certain way to full diabetes, which ISN'T reversible.
If you're overweight, you need to reduce that ( easier said than done !I know) A low carb diet will help with that too.