How to Pass the Glucose Tolerance Test during pregnancy. These tips for pregnant moms will help you pass the gestational diabetes test during your 2nd trimester. Know what to eat the night before the glucose tolerance test, what not to eat, how to reduce your risk of gestational diabetes, and more! The difference between the 1 hour and 3 hour glucose test and glucose drink alternatives (jelly beans) you can try! Perfect article for new moms nervous about gestational diabetes.