Is “Small, Medium, Large” the Future of Meal Bolusing?

I was recently stopped in my tracks by a recent post on LinkedIn by Robert Gabbay MD, PhD, who was discussing a study that looked at a more flexible way of bolusing for food with an insulin pump, into small (15-20g), medium (40-70g) and large meal (60-90g) categories, (i.e. the 20/40/60 rule), vs. the more traditional fixed counting of every signal gram of carbohydrate. 

The Research

A 2024 peer-reviewed research paper in Diabetes Technology & Therapeutics reported 12-month results from a randomized controlled trial comparing precise carbohydrate counting with a simplified meal-announcement approach in adolescents with type 1 diabetes using the MiniMed 780G system. The study was led by Goran Petrovski and colleagues at Sidra Medicine in Qatar, titled “Twelve-Month Follow-up from a Randomized Controlled Trial of Simplified Meal Announcement Versus Precise Carbohydrate Counting in Adolescents with Type 1 Diabetes Using the MiniMed™ 780G Advanced Hybrid Closed-Loop System.”

pmc.ncbi.nlm.nih

The Question

For many adolescents and young adults with type 1 diabetes, counting every gram of carbohydrate can feel like a full-time job. This study examined whether this flexible approach to bolusing would provide comparable results when used with an advanced hybrid closed-loop insulin system.

The Goal

The goal was to determine whether reducing the calculation burden could still support safe and effective glucose management.

What they found

After 12 months, both groups maintained average glucose control within recommended targets. HbA1c remained below 7% at each measured time point, and there was no statistically significant difference in HbA1c between the two approaches. It is interesting to note that though not statistically significant, the A1C of the Flex group was lower than the Fix group. [liebertpub]

Carb counting still had an advantage to TIR

Although the Flex group performed well, it did not produce exactly the same results. At 12 months, participants using precise carbohydrate counting spent about 80.1% of their time in range (TIR) of 70–180 mg/dL, compared with 72.9% among those using the simplified meal approach. [liebertpub]

This suggests that carbohydrate counting may still provide more precise insulin dosing and better time-in-range, particularly for people who are comfortable with the process and able to estimate portions accurately.

However…

1.  After 3 months, 15 out of 17 participants who had been part of the Fix group, and were comfortable with carb-counting, chose to switch to Fex bolusing.  

2. Patients in the fix group reporting significantly fewer meals per day than those in the flex group [liebertpub]

What Does this All Mean?

The findings are important because it shows that diabetes management is not performed by a robot; it is painstakingly managed by an emotional human being who is juggling diabetes in one hand, and their life in the other. Life does not like to wait for a detailed computation that carb calculation requires. In my mind, it is not surprising that the Fix group just decided not to eat as many meals as the Flex group did, considering the brain power required just to eat or that 15 out of the 17 people in the Fix group switched to the Flex group.  That must say something about the burden that carb-counting is. 

At the end of the day, what is the tradeoff? While not as good for TIR as the Fix system, the Flex system is much better than not bolusing at all. For teens and young adults, the Fix system could be a game changer, making diabetes management easier during school, sports, travel, or meals with friends. Basically, effective diabetes care must balance glucose outcomes with sustainability and quality of life.

What do you think? I’d love to know. Post your comments below. 

This post is for educational purposes and should not replace individualized guidance from a diabetes care team.

References:

“Twelve-Month Follow-up from a Randomized Controlled Trial of Simplified Meal Announcement Versus Precise Carbohydrate Counting in Adolescents with Type 1 Diabetes Using the MiniMed™ 780G Advanced Hybrid Closed-Loop System.”pmc.ncbi.nlm.nih,  February 5, 2024, and in the March 2024 print issue of Diabetes Technology & Therapeutics, volume 26, supplement 3, pages 76–83. Its DOI is 10.1089/dia.2023.0429.

https://www.liebertpub.com/doi/full/10.1089/dia.2023.0429 2. https://pmc.ncbi.nlm.nih.gov/articles/PMC10890955/ 3. https://udem.insel.ch/en/teaching-and-research/focus-topics/diabetes/smash