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Diabetes Clear Liquid Diets and Insulin

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This information was reviewed and approved by Dthia Kalkwarf, RN, CDE, BC-ADM (3/1/2019).

Your doctor has suggested a procedure that requires you to be on a clear liquid diet before the procedure. If you have diabetes and take Insulin, this Test Facts will help you follow the clear liquid diet and control your blood sugar (glucose) levels. If, after reading this information you are still unsure as to how to dose your insulin, check with the doctor who prescribes your insulin for advice.


Types of Clear Liquids

  • Clear liquids that contain sugars include:   Gatorade, G1,2,3, sodas, fruit juices, popsicles, regular Jell-O.

  • Clear liquids that do not contain sugar include:  Unsweetened tea, black coffee, water, diet sodas, sugar-free Jell-O, clear broth, bullion, Vitamin water (Vitamin water has a small amount of sugar) GoLYTELY and HalfLYTELY do not contain sugars.

  • Drink at least 8 ounces, but not more than 16 ounces, of a sugar-containing liquid at usual mealtimes while on the clear liquid diet. 


Mealtime (Short-Acting) Insulin

  • Do not take mealtime insulin on the day of the clear liquid diet.

  • Start again when you are eating meals.


Long-Acting Insulin

  • If you usually take long-acting insulin in the morning, take half your usual dose on the morning of the clear liquid diet day.

  • If you usually take it at bedtime, take half your usual dose the night before the fasting day.

  • After the fasting is over, resume your usual dose(s) of insulin.


Mixed Insulins (70/30 mix, 75/25 mix, 50/50 mix)

  • A general rule is to just use HALF doses on the day of the fast.


Treating Low Blood Sugar

  •  While on clear liquids, check your blood sugar four times a day (at your usual mealtimes and at bedtime) or anytime you have symptoms of a low blood sugar.  Common symptoms of a low blood sugar may include: shakiness, dizziness, sweating and headache. If your blood sugar drops under 70, you should immediately take 15 grams of glucose gel (1 tube). This will usually raise your blood sugar by 50 points in about 15 minutes. Be sure to re-check your blood sugar 15 minutes after treatment, to make sure it is over 70. If not, take a second tube of gel.


Driving home after procedures

  • Depending on the procedure National Jewish may recommend a family member or friend drive you home.

  • If you drive home, National Jewish Health strongly recommends that you check your blood sugar every time before driving a car.  Your blood sugar should be 100 or higher before driving.

  • Keep fast-acting sugar with you in your car (glucose gel, glucose tablets or hard candy).



  • If you are still unsure as to how to dose your insulin, check with the doctor who prescribes your insulin for advice.

  • Bring your glucose meter and test strips to National Jewish Health on your test day.


How do you get to your procedure?

If you are being seen at National Jewish Health, on the day of your scheduled test, check in at the Front Desk. If you have questions before or during your test please call 303.398.1355. Also, if you need to cancel the appointment or change the time please call.