Diabetes and colonoscopy

The following are guidelines only – more specific questions can be handled by your health care provider

When you have diabetes, anything that causes you to change your usual meal routine requires special planning to safely manage blood glucose levels.

Insulin and Diabetes Pills

If you have diabetes, it is important to monitor your blood sugars frequently while doing the bowel preparation.

  1. Take only ½ of your usual dose of insulin or pills on the day before your colonoscopy, when you are taking only clear fluids
  2. Do not take any diabetic medications on the morning of the colonoscopy. Except-if you only take insulin, take half of the usual dose of long acting insulin in the morning.
  3. Check your blood sugar levels at home before all meals, before bedtime and on the morning of your exam. Check if you have concerns or if you have symptoms of low or very high blood glucose levels
Tips for the Colonoscopy
  1. Ask to schedule the colonoscopy early in the day so that you can eat afterwards and take your medication as close to the usual time as possible
  2. Check your blood glucose level before all meals and at bedtime on the day before and on the day of the colonoscopy
  3. Check your blood glucose level at any time you have concerns or if you have symptoms of low or very high blood glucose levels
  4. Bring your blood glucose meter, test strips, a low blood glucose treatment and a snack with you on the day of the colonoscopy. Do not have any solid food before the colonoscopy and stop all liquids two hours before the colonoscopy
Clear Liquid Food Choices:
  • Aim for 3 starch choices or 45 grams of carbohydrate at meals and 1-2 starch choices or 15-30 grams of carbohydrate for snacks
  • Avoid foods that are red or have red dyes (cherry, berry, or grape flavors)
Sample of Clear Liquid Choices with Approximately 1 Starch Choice or 15 grams of Carbohydrates:
  • Apple juice (4 ounces)
  • White grape juice (4 ounces)
  • Sports drink such as Gatorade (8 ounces / 250 ml)
  • Gelatin (Jell-O), regular sweetened (1/2 cup / 125 ml)
  • Regular lemon-lime soft drinks (Sprite or 7-Up)
  • Sugar (for coffee or tea) (1 teaspoon or packet)
Food Items Without Carbohydrates:
  • Fat-free broth, bouillon, or consommé
  • Diet clear soda
  • Coffee
  • Tea, unsweetened or diet
  • Seltzer
  • Flavored water
Sample Menu

Breakfast (3)
Apple or white grape juice (1/2 cup) and
Regular sweetened gelatin (1/2 cup) and
Tea with lemon

Lunch (3)
Consommé (1 cup) and
Regular sweetened gelatin (1/2 cup) and
Lemon-lime beverage

Dinner (4)
Consommé (1 cup) and
Regular sweetened gelatin (2 cups) and
Diet lemon-lime beverage