I am diabetic. I went from an A1C of 4.5-4.9 for years, to 13.2 within 6 months. Who lnows what the trigger was. I did not want to wind up injecting insulin the rest of my life. I do take metformin and januvia, but if you are pre-diabetic here are some suggestions which i do myself:
Cinnamon: it has been shown to regulate blood sugar
Chromium Picolinate: same as Cinnamon
Psyllium: Natural source of dietary "clean-you-out" fiber
Sleep: Good bed rest is essential
Walk: It's the most natural excercise...we used to all do it before the advent of the automobile
Glycemics: keep in mind certain starches/sugard go straight to the bloodstream. So avoid potatoes, breads and such and if you must eat them, add some fat (butter, sour cream, oil) to reduce the glycemic conversion