One hour glucose test - suggestions?

My doctor acted like this test was no big deal and completely independent from everything else I eat that day.  So, I scheduled it in the afternoon thinking it wouldn't matter.  But now I've had quite a few people tell me it should be done first thing in the morning, and that I should fast or only eat a little protein to have a better chance of passing.  What has been your experience? Has anyone else taken it in the afternoon and been fine, or should I reschedule?