Ugh, I'm so sorry! Was this the one hour test or the three hour test?
With all of my RPL testing, they discovered that I have pre-diabetes which basically just means I'm at a pretty high risk for developing diabetes or gestational diabetes in the next few years.
The eating advice they gave me is basically the same as the eating advice they would give someone with gestational diabetes. Eat plenty of fruits and vegetables and lean proteins (chicken, turkey, fish that's considered safe for pg, beans, nuts, peanut butter - but compare labels for sugar content), whole grains (wheat, barley, spelt, quinoa etc...) instead of anything white/refined/processed. Dairy is ok, but watch out for fruity yogurts which are full of simple carbs (sugar, in this case) and other flavored dairy products.
I also cut out all fruit juice and cereal at my dietician's recommendation. Now I have the whole fruit instead of a glass of juice and I eat steel cut oats or a boiled egg and piece of fruit for breakfast most of the time.
Finally, I cut down portion sizes, but I don't know how much of that you want to do during pregnancy. I find it easy to cut portions at home, but a lot harder at a restaurant, so I'm trying to eat out a little less too.