Argh, I've just realised I wrote this talking about diet and cholesterol when of course you're looking at diet and lowering blood sugar. Same comment that there's not much else you can change of course. Something I did find helpful when I was getting out of the prediabetic zone was Jesse Inchauspe (the "Glucose Goddess")'s hacks to lower blood sugar. Although not diabetic, she tracks her blood sugar with a monitor and figures out what affects it. Her recommendations, which I found pretty easy to incorporate, were to eat vegetablse/salad, or protein if you're not having those, before carbs in a meal, don't eat carbs on their own but instead with protein, have a savoury breakfast (this improves blood sugar control all day) and exercise after meals containing carbs (this doesn't have to be a huge workout, she found thirty squats were enough to drop her blood sugar. I alternate squats and hand weights after dinner, and do housework after lunch). That might help keep you on the right side of the prediabetes zone.