As others have said above, if you can lose some weight then you may never stray in to the diabetes zone.
Pre diabetes is a bit of a vague concept as it is measures by blood sugar, its a bit like looking at a paint chart and deciding where black starts on a range of white to black!
Low GI foods would be a good idea as they reduce the spike of sugar after a meal (this stimulates a spike of insulin).
Your body basically is becoming resistant to the insulin that it makes, don’t underestimate the good that exercise can do to restore this.
Diabetes uk is a good website to look at, there is lots of nonsense on the web related to diabetes!