How to fast before a glucose tolerance test
Your doctor has asked you to have a glucose tolerance test taken. You know you need to fast beforehand, but you're not sure for how long and if you can take any prescribed medications or not. Here's how to fast for the glucose tolerance test so you get an accurate blood sugar result.
Do a trial fast to see how you react. If you're in the habit of eating every 4 hours, try missing a meal and see how you feel. Do this at least a week before you're scheduled to fast for the glucose tolerance test.
Schedule the test early in the day. If you schedule the glucose tolerance test in the afternoon then you're wide awake, most likely moving around and are used to eating and drinking so you'll be more hungry. With a morning appointment you won't be missing two meals during the fast by the time you have your blood drawn for the glucose tolerance test.
Inform your doctor about any medications you're currently taking, and if you should continue taking them during the fast or not. Some medications must be taken, while for other medications it's safe to temporarily discontinue use during the fast.
Eat light the night before you begin your fast. It may seem like you should bulk up with a big meal to make up for the time spent fasting, but eating lighter helps your digestive system slow down. Keep things like fatty and sugary foods away.
Fast for eight to 12 hours before you have your first blood taken. The glucose tolerance test includes a blood draw before you drink a sugary liquid, and an hour after that as well. If you're doing a three-hour glucose tolerance test, then it's one blood draw every hour for three hours.
Select your first meal after the fast carefully. After a fast, you need to gently re-introduce food into your digestive system. Choose foods that you know are easy for you to digest. Stay away from greasy and gas-producing foods for your first meal after the glucose tolerance test.