You're doctor should have told you, but to get an accurate reading of how your body handles an intense amount of sugar at one time, you should be fasting for 8 hours.
Just make sure you dont eat anything extra sweet or fast food within an hour or 2 of drinking the bottle because it can skew your results and force you to do the 3hr.
No you don't have to fast for the 1 hr. You only have to fast for the 3 hr.

I will be 41 :/
Short Luteal Phase?
I've just started temping because I believe that the reason I haven't had a BFP yet, after 20 months, is because I believe I may have a Luteal Phase Defect.
Yesterday I went out with my boyfriend went to watch a movie, me and him don't live together yet. but point is yesterday when he was dropping me off his like sleep over at my house witch the mom and dad lives. I said no,
his response was why is everyone deciding or making choices for you and their going to do the same with the baby, when I know that's not true. what he thinks is that my mom tells me not to sleep over. So he left all mad. and I felt in my heart that he went on and cheated on me...
Things I never thought I'd say...
Until I became a mom:
My doc said I didnt have to fast for the 1 hour..just not to have anything sugary for breakfast that morning. I scrambled myself some eggs & drank a bottle of water & passed without a problem.