I was diagnosed as being barely Prediabetic also. However, with frequent testing I discovered that a chunk of baguette bread spiked my blood sugar above 200/11.1 According to the excellent site:
www.bloodsugar101.com, at 140/7.8 pancreatic beta cells begin to die, accelerating the progression of Type 2 diabetes. I eat low carb, but in the beginning, I tested at 15 minute intervals to see which foods spiked my blood sugar the most. Now that I pretty much know what certain foods do to me, I reduce or avoid them all together with the goal of staying below 140/7.8 at all times. I have found perfectly good test strips online through Amazon, making testing often affordable.