I had to fast for eight hours before the test
It depends on your doc. Mine told me not to have a soda or candy bar or anything extra sugary or full of starch (which will turn to sugar) but I didn't have to fast beforehand. At least not for the 1 hr. test. If you fail the 1 hr test and are asked to take the 3 hr test its best if you fast before.
I had to starve myself from 10 o'clock the night before but your aloud to drink water my appointment was 9am xx