Rationale of the Week | Getting to the Right Carb Count

Our September 7th Question of the week quizzed test takers on carb counting. 55% of respondents chose the correct answer. This was a hard question. Figuring out how much insulin to cover carbs is an important topic to review, so we can pass on correct info to people living with diabetes.

Before we start though, if you don’t want any spoilers and haven’t tried the question yet, you can answer below: Answer Question

Question: LS uses an insulin pump and CGM.  Most recent report reveals LS is running 56% time in range and 44% above target range. LS asks for help with carb counting.  A typical breakfast includes: ½ cup of milk, 2 tablespoons peanut butter and 1 piece whole grain bread, 3 oz’s of grapes and one cup of black coffee with Splenda. LS’s insulin to carb ratio for breakfast is 1:12, for lunch and dinner is 1:15.

Based on this, how much insulin does LS need for breakfast?

Answer Choices:

  • 3.1 units
  • 2.4 units
  • 3.0 units
  • 2.5 units

As shown above, the most common choice was option 3, the second most common answer was option 1, then option 4, and finally option 2.

Getting to the Best Answer

If you are thinking about taking the certification exam, this practice test question will set you up for success. Test writers anticipate possible answers based on the details in the question. They will wave those “juicy answers” right under your nose. Your job is to weed through the particulars, do careful math, be familiar with the exchange list and choose the BEST answer.

Diabetes Exchange List – a brief summary of serving size and carbohydrate counts for common foods. Excellent study tool for the exam.

Here are the carb counts of the foods listed:

  • ½ cup of milk = 6gms
  • 2 tablespoons peanut butter = 0
  • 1 piece whole grain bread = 15gms
  • 3 oz’s of grapes = 15gms
  • one cup of black coffee with Splend = 0 carbs
  • Total carbs for this meal =36gms

LS’s insulin to carb ratio:

  • breakfast is 1:12
  • lunch and dinner is 1:15

Answer 1 is incorrect. 23.97% chose this answer, “3.1 units.” If you chose this answer you are so close. For the exam, remember that one cup of milk has 12gms of carbohydrate (not 15gms). Please see the link to the exchange list for the carb counts of common foods.

Answer 2 is incorrect. 9.98% of you chose this answer, “2.4 units.” If you chose this answer, you may have used the lunch/dinner insulin to carb ratio of 1:15 instead of the breakfast ratio of 1:12. This is an easy mistake to make, so make sure to read the question carefully and take your time doing the math. You got this.

Answer 3 is correct. 55.32% of respondents chose this answer, “3.0 units.” GREAT JOB. This is the best answer. The total carb intake for LS is 36 gms. Since the Insulin to Carb (I:CR) ratio for breakfast is 1:12, to find out how much insulin LS needs for breakfast, just divide gms of carb by the I:CR or 36 / 12 = 3 units.

Finally, Answer 4 is incorrect. 10.73% chose this answer, “2.5 units.” If you chose this answer. there are 2 things to be aware of: one cup of milk has 12gms of carbohydrate (not 15gms) and you may have used the lunch/dinner insulin to carb ratio of 1:15 instead of the breakfast ratio of 1:12. These are easy mistakes to make, so make sure to read the question carefully, be familiar with common carbs and take your time doing the math. You got this.

Diabetes Exchange List – a brief summary of serving size and carbohydrate counts for common foods. Excellent study tool for the exam.

We hope you appreciate this week’s rationale! Thank you so much for taking the time to answer our Question of the Week and participate in this fun learning activity!


Want to learn more about carb counting and more?
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  • Diana Isaacs, PharmD, BCPS, BC-ADM, BCACP, CDCES – Educator of the Year, 2020
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  • Ashley LaBrier, MS, RD, CDCES, Diabetes Program Coordinator

In addition to informative lectures, we also use group activities and case studies to highlight the essential knowledge, skills, and strategies needed to succeed in diabetes education today!

CEs: Includes over 30 CEs
Program Info: 2021 Diabetes Educator Course Flyer & Schedule (subject to change)
Speakers: View Conference Faculty.
Dates: Your Registration fee includes access to FREE podcast and all recorded webinars for one year from your registration date.

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2021 Diabetes Educator Course Flyer & Schedule (subject to change)


Virtual DiabetesEd Specialist Conference Basic | Oct. 6-8 | 30+ CEs

Basic virtual program for $359 includes:

  • Presentations by our team of experts
  • Q & A Session with the instructor after each webinar
  • State-of-the-art review of current diabetes care and technology.
  • Resources for each session
  • Access to FREE podcast and recorded webinars within a week of each live session for one full year.

2021 Diabetes Educator Course Flyer & Schedule (subject to change)


Team of Experts: Our team of expert faculty has been fine-tuning this course for over fifteen years and we know what you need to succeed! In addition to informative lectures, we also use group activities and case studies to highlight the essential knowledge, skills, and strategies needed to succeed in diabetes education today!


Bonus Courses worth 12+ CEs, FREE

When you register for our Virtual Course, you have immediate access to these Bonus DiabetesEd University Online Courses – for FREE!

  • Test Taking Toolkit – Over 200 sample test questions!
  • Level 2 – Assessing and Promoting Well-Being: From Population Health to a Person-Centered Approach 1.5 CEs
  • Level 2 – Hospital and Hyperglycemia 1.5 CEs
  • Level 2 – Hyperglycemic Crisis, DKA and HHS Standards 1.0 CEs
  • Level 2 – Meds Management Update for Type 2 – 1.5 CEs
  • Level 2 – Setting up a Successful Diabetes Program 1.5 CEs
  • Level 2 – Pregnancy and Diabetes 1.5 CEs
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  • Level 2 – Older Adults and Diabetes 1.5 CEs
  • Mindfulness and Compassion in the Diabetes Encounter – 1.0 CE

2021 Diabetes Educator Course Flyer & Schedule (subject to change)


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