i have to take the 3 hour...failed the one hour by 5 points

My OB office sent out a sheet of a carb load diet for 3 days before the test, basically they want me to eat 5 extra servings of carbs each day. This seems like a lot to me...did anyone else have to do this???
Re: special diet before 3 hour glucose test?
Marriage: 12.18.04
DD1: 5.19.10
DD2: 4.11.12
I just barely failed the 1hr with each pregnancy but passed the 3hr both times. I never had to do any special diet.