A veggie fruit diet-will drive up you Hgb 1AC- it is mainly glucose
But if you really "like it"
there are ways around that problem
I seem to remember one member hear- SWEARS by coconut oil in his coffee??
The extra fat will mean you'll eat fewer carbs-and he made some BIG CLAIMS for the coconut oil being HEALTHY??
I have no idea if it is "healthy" sounded gross when it is much simpler to use MILK of something more palatable-but perhaps he had a point.

If you are really concerned about this pre-diabetic DX-(what were your numbers)-
you can certainly "cure" that lab test with a tiny pre-meal insulin dose.
It will drop you Hgb 1AC
Are you a straight veggie-no milk no eggs??
Oh one other potential problem with a VEGGIE DIET- it makes you HUNGRY
A diet higher in fat and protein(high bio value protein) will "make you less hungry,so you can lose than 15 lbs"

If I were you-and you number was minimally elevated-just forget it
Hell you are probably a Lane Controller and will get ROAD RAGED long before you croak for DM
On the other hand-if it was 6.2%- I would
1)Change my diet-more fat more protein-fewer carbs
2) or take a low dose of insulin before meals-and stay veggie
3)Or drink coconut oil or peanut oil or olive oil-whichever you can gag down-and consume less carbs(all carbs end up as glucose-and despite all sorts of BS folks claim about "better carbs" they all become glucose pretty quickly) sure some produce a lower slower peak glucose-but that might mean more actual area under curve-lower insulin spike-and HIGHER HGB1AC since your Hgb is exposed to excess glucose for LONGER periods of time.

Or just ignore it if it is minimal-you'll get hit by a car

PS Can't remember if you are a FRAPPER or a LCer-in any case we will probably all get run over by a car-doored Easy Rider-ed (hey I live in outside NOLA- )
PM me if you want more detail-but I suspect you have more than you ever wanted