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Some Glycemic Index Strategies to Curb the Post-Meal Spike

I couldn’t begin to count the number of times in my life that despite a solid carb counting estimation and a reasonable bolus strategy that I’ve been surprised by what happens to my blood sugars 1-2 hours after eating. 

I often see photos on social media posted of CGM graphs without any peaks and am frequently asked by clients about how to reduce or improve post-meal glucose results. It’s also one of the reasons I relish participating in the monthly IDS Food Challenges (check out our Facebook page) where our team of clinicians takes on notoriously challenging foods and post our CGM graphs with our bolus strategies and post-meal glucose.

Spoiler alert: even the pro’s don’t always get it perfect ?

A wise Gary Scheiner once wrote:

“The reason blood sugars spike very high after eating for many people with diabetes is a simple matter of timing. In a person without diabetes, consumption of carbohydrates results in two important reactions: the immediate release of insulin into the bloodstream and the production of te hormone amylin. Insulin produced by the pancreas starts working almost immediately and finishes its job in a matter of minutes. Amylin keeps food from reaching theintestines too quickly (where the nutrients are absorbed into the bloodstream). As a result the moment blood sugar starts to rise, insulin is there to sweep the excess sugar into the body’s cells. IN most cases, the after-meal blood sugar rise is barely noticeable.

However, people with diabetes are like baseball players with very slow reflexes. We’re in the batter’s box facing a pitcher who throws ninety-mile-per-hour fastballs; by the time we swing, the ball is already in the catcher’s mitt. Rapid-acting insulin that is injected (or infused by a pump) takes ninety minutes to peak and three to five hours to finish working. And don’t forget about the lack (or deficiency) of amylin; food digests even faster than usual. When food hits the bloodstream long before insulin, blood sugars spike ver high and then come crashing down later when the insulin finally kicks in.”
– Think like a Pancreas Third Edition, p. 274-275

exhausted woman

If you’re struggling to hit your post-meal glucose targets, chat with your IDS clinician about optimizing your insulin to carb ratio. In the meantime, here are some other strategies to consider:

  1. Pre bolus timing- Rapid acting Insulin (Humalog, Novolog, Apidra) takes a bit of time (10-15 mins) to activate in our system. That means for most meals we need to get the insulin in before our first bite of food.  If you aren’t already in the habit of pre-bolusing, give it a try for a week and see how your post-meal numbers are impacted.
  2. Can’t pre-bolus? I can relate! Sometimes between the rush of preparing a meal and feeding my toddler, I simply run out of hands or forget. If this sounds like you, it may be time to try ultra-rapid acting insulins. There are new insulins available (FIasp and Lumjev) that have a shorter time to activation in your system (2 minutes) and also work harder during the time when glucose raises the most (1-2hours). This drastically shortens the time that is needed for the insulin to get working and respond to the glucose rise after a meal. After trying these medications, I was impressed with the result (but also distracted by how much the infusion/injection site BURNED).
  3. Low Glycemic food choices- When I first started wearing a CGM, I was astounded by the glucose effects of several foods I was eating. My go-to breakfast at the time was cereal, and many of us have had the experience of watching a morning breakfast cereal spike. You may have heard of the glycemic index- it’s a helpful tool that can steer you towards carbohydrate choices that will have a lesser impact on your glucose results. I like to think about the glycemic index as smart carbs, especially when choosing from low glycemic foods with a GI score less than 55. Though many of us who use a CGM can observe the impact of glycemic index on our food choices, research was not able to capture this as an effective strategy for glucose management until recently. A 2021 review of evidence finally found that a low glycemic intake was an effective strategy for reducing hemoglobin A1c, LDL, triglycerides, body weight, BMI, and CRP (a marker of inflammation). Even more promising, the glucose lowering effect of using a lower glycemic eating style further reduced A1c results!
  4. Multiple food groups: It’s not uncommon for me to see glucose spikes for meals and snacks that only contain carbohydrates. Estimating our carb intake is important, but not at the expense of only eating carbohydrates! Take off your carbohydrate goggles and try to balance your meals and snacks with more than one food group. Adding protein or fat can really help balance things out.
  5. Find your carbohydrate threshold- How much carbohydrate should I be eating during a meal? Managing the amount of carbohydrates consumed at a meal is another simple strategy to try. As you assume, it can be easier to achieve post-meal glucose targets at the lower end of a threshold. This is highly variable, but many find 30-60 grams for meals and 15 grams or less for snacks as a reasonable target.


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