I had prediabetes's and fully reversed it by sensible diet & some exercise, its really simple, just stay right away from high sugary carbs, look for low GI foods, if you like your bread only go for very high fibre bread, breakfast cereals like bran, porridge etc, the higher the fibre the better.

Main meals, fish, red meat, chicken [without any fat of course] with vegetables or salads are all fine, soft drinks, sweets, , anything containing high sugar content has to go out the door.

If you can do some exercise for about 20 minutes a day for 3 or 4 times a week ,it will defiantly help, i use to go to my local pool and just walk up and down the lanes when they are not busy, lots of people do it for all kinds of med problems, the best part is that its good cardio exercise and non weight bearing but its best to get to the pool real early before to many people come, i must get back in the routine myself , the weight should just drop off you, it really doesn't take all that long at all and you will start to feel the benefits nearly straight away, well it did for me anyway, i knew about those supplements, but its real easy to do it naturally.
good luck
Brian