Diet preparation for 3-hr glucose tolerance test

Diet Preparation for 3-Hr Glucose Tolerance Test

If you are prescribed a glucose tolerance test by Women’s Health of Chicago, it’s important to use this diet in preparation for the test.  If you have any questions, feel free to call us.

Important Note: This diet, sample menu and substitution, is only for preparation for the Glucose Tolerance Test, and should not be confused with substitution lists in any Diabetic Diet.

Follow directions as precisely as possible:

  • Follow this diet for 3 full days before the test. This is important so test results will be reliable.
  • You will not gain a significant amount of weight after only three days of the diet.
  • Any additional food you desire may be eaten, but please do not delete any portions.
  • For the final 12 hours before the test, no food, no liquids, no tea, no coffee, no smoking and no gum. Water is allowed. Do not fast for more than 16 hours.

You should take any medications on the same schedule prescribed by you physician, such as blood pressure or heart medication. Do not take any over-the-counter medications for 12 hours before the test, such as cough or cold preparations, vitamins, aspirin, etc. All testing begins the morning after a night’s sleep (i.e. no working the night before).

About the Sample Diet

Be sure to eat 150-200 grams of carbohydrate for 3 full days before the test. The approximate grams of carbohydrate are in parentheses following each menu item. You may feel
free to substitute from the table below.


  • 8 oz. orange juice (20)
    1 slice toast (15)
    1 tbsp. jam or jelly (15)
    One cup dry cereal (20)
    8 oz. milk (10)

Mid-morning Snack

  • 20 grams of carbohydrate from list below


  • 1 sandwich (30)
    8 oz. Wheat Thin crackers (10)
    8 oz. milk (10)

Mid-afternoon Snack

  • 20 grams of carbohydrate from list below

Evening Meal

  • Meat (your choice)
    1 medium potato
    One serving vegetables or salad (10)
    1 pear (20)
    8 oz. milk (10)

Evening Snack, if desired (day 1-2 only)

  • 20 grams or carbohydrate from list below
10-15 Grams 20 Grams 30 Grams 50 Grams
1 apple 1 banana 8. oz apple juice 1 piece of iced cake
3 arrow roots 1 corn-on-cob 1 bagel 1 piece of pie
1/2 cup blueberries 1 cup dry cereal 6 dates 8 oz. prune juice
1 slice bread (not puffed) 6 oz. cranberry juice 3 Fig Newtons 1/2 cup raisins
2 med. carrots (raw) 3/4 cup cream of wheat 1 cup ice cream 1 cup fruit yogurt
1/2 cup cooked cereal 1 cup fruit cocktail 1 small potato
1/2 grapefruit 1 whole graham cracker 1 small sweet potato
12 grapes 4 oz. grapejuice 4 prunes
8 oz. milk (skim ok) 1 hamburger roll 1 cup spaghetti
1 medium peach 1 medium pear 2 toaster waffles (Eggos)
2 cups popcorn 8 oz. orange juice 1 slice of pizza
1 cup strawberries
8 oz. tomato juice
1 cup tomato soup
1 cup plain yogurt
4 vanilla wafers

Important Considerations & Reminders for Glucose Tolerance Test

  • On the third day of your diet, eat nothing (not even toast) and drink nothing, except sips of water after 10:00 p.m. and until your test is complete.
  • First a fasting blood sample will be drawn, then you will be given a sugary liquid to drink.
  • Each hour after the drink, blood will be drawn. This will be done three times.  It is important that the blood be drawn at exactly one-hour intervals, so please be available at the indicated times.
  • Please bring something to read or do while quietly sitting until the test is over.
  • Do not eat, smoke or drink anything except water during the test. Sips of water should be taken only if you are very thirsty.
  • After the last blood draw, you may leave the laboratory. At that time, you may have your lunch, and resume your normal diet.
  • If you are unable to eat your usual diet, please inform your health care provider.
  • Maintain your usual activity level on the days preceding the test.

Download the “Diet Preparation for the Glucose Tolerance Test”  from the Patients Welcome Page.

Sourced from, and adapted with permission from the University of California, San Francisco, OB Clinic.