Dietary Preparation For Three-Hour Glucose Tolerance Test

If a Three-Hour Glucose Tolerance Test has been scheduled, it is to determine if you have Gestational Diabetes. Please use the following dietary instructions to ensure that your test results are as accurate as possible:

Getting Ready

  • Eat at least three meals a day starting three days before the test.
  • The meals should contain many carbohydrates (“starchy” foods such as breads, cereal, pasta, rice, potatoes, corn, bananas, yogurt, cookies. . .)
  • In addition, eat one of the following extra carbohydrate servings each day to challenge your body’s ability to process sugar:
    • 2 slices of bread
    • 1 piece of cake
    • 1 candy bar
    • 1 can non-diet soda
  • Do not “diet” before the test as dieting may cause inaccurate results.


The Night Before the Test

  • Do not eat or drink anything except water after midnight.
  • Do not smoke, chew gum, or eat cough drops or hard candy.


The Test

  • Report to the laboratory at your scheduled appointment time.
  • A lab technician will draw a fasting blood glucose sample and then will ask you to drink a bottle of Glucola, a high sugar drink.
  • Blood samples will be drawn at one, two, and three-hour intervals.
  • You may drink water during the three-hour test but must delay eating until after completion of the test. Consider bringing a snack with you to the lab to eat immediately following the test.
  • You may wish to bring reading material with you to the laboratory to pass the time.