To Eat, Or Not To Eat

So at my last ultrasound they said i had partial placenta previa. Today i have another ultrasoundto see if it's resolved, AND my glucose test. AND talking to financial dept before we leave about our global. So it's going to be a minute there. I want the best possible read for my glucose, but I've read that one way to get best read was to not eat before appt. Its 9am my time right now, appt time is 1:30. I don't want to feel sick or ticked off because I'm hungry that long. What do i do?