I am going in for my glucose tolerance test in two weeks. This too is my second pregnancy, and I failed it with my first pregnancy to a very negligible amount, but after the 3 hour glucose test - everything came back fine. I recently asked my doctors the exact same question you have here. My test is also in the afternoon, and this is how I was instructed: Breakfast, 1 piece of whole wheat toast and 1 egg. Snack: vegetables such as carrot sticks. Lunch: Something with protein such as grilled chicken and an avocado. Only drink water, no candies or chewing gum, and try to watch your sugar intake the day before the test as well. I was instructed specifically NOT to fast. I was also told to avoid fruits, so if I were you, I wouldn't have those the day of the test. Also, do not eat or drink anything after you drink your glucose solution. Best of luck!