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Everyday Challenge: Digest This

How timing may affect blood sugar management

Several times, my blood sugar has gone low right after lunch, then went sky-high several hours later. I think I counted my carbs accurately and calculated my insulin as I always do, so what gives?

How frustrating! You’ve taken the time to count carbs and figure an appropriate insulin dose, only to wind up on a blood sugar roller coaster. It sounds like you’ve discovered the “Fourth Dimension” of diabetes management: Time. Or timing, to be more exact.

You see, it may not be enough to take the right amount of insulin to cover a meal … the insulin should also be taken at the appropriate time in order to be most effective.

The goal is to have the mealtime insulin (also called a “bolus”) peaking at the same time the food is raising the blood glucose. But this isn’t always easy, because some meals and snacks digest faster than others. The term “glycemic index” was coined to rate foods based on how quickly they raise the blood glucose. Many carbohydrate-rich foods, such as breads, potatoes, rice and cereals, convert into blood glucose very quickly. Others, such as beans, milk, pasta and chocolate, take a while longer. A meal that consists of mostly low-glycemic-index (slowly digesting) foods is likely to take several hours to raise the blood glucose. (Read about the glycemic index for more than 2,480 foods.)

Since rapid-acting insulin peaks 1 to 2 hours after it is taken, if one takes mealtime insulin soon before eating, it may peak before most of the food has had a chance to digest, potentially resulting in a drop in blood sugar soon after the meal, followed by a rise a few hours later.

A number of other situations may result in a delayed blood sugar rise. These may include:

You may wish to work with someone on your healthcare team to slow down the action of the mealtime insulin in these situations. Your team may suggest taking the bolus later, such as immediately after the meal or 30 minutes after eating, or other adjustments to your treatment regimen.

Gary Scheiner, MS, CDE*, is a Certified Diabetes Educator and Masters-Level Exercise Physiologist who has lived with type 1 diabetes for more 28 years. He was named 2014 Diabetes Educator of the Year by the American Association of Diabetes Educators, and has written six books, including Think Like a Pancreas. Scheiner and his clinical staff provide diabetes management consultations worldwide via phone and the Internet through his practice, Integrated Diabetes Services. Scheiner is a paid contributor for The DX. All opinions contained in this article reflect those of the contributor, and not of Sanofi US, its employees, agencies or affiliates.

*“Certified Diabetes Educator” and “CDE” are certification marks owned and registered by the National Certification Board for Diabetes Educators (NCBDE). NCBDE is not affiliated in any way with Sanofi US. NCBDE does not sponsor or endorse any diabetes-related products or services.

© 2015 The DX: The Diabetes Experience

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