Case Study: Effects of Carb Counting with Type 1 Diabetes

By Sherri Shafer

Coral took one unit of rapid-acting insulin for every 15 grams of carbohydrate. She hadn’t been completely satisfied with the results. Sometimes her blood-glucose levels were higher or lower than expected. Upon close inspection several issues were identified:

  • She was putting in effort but had gaps in her accuracy. She never counted the carbs in nonstarchy vegetables, such as green beans and broccoli. Coral was diagnosed at age 9, and at that time she didn’t really eat many vegetables, so her diabetes team told her family that vegetables were “free.”
  • Another issue: No one had ever told her to subtract the fiber from the total carbohydrate when reading food labels. She’s now 28 years old and eating lots of vegetables and whole grains. After nearly 20 years of diabetes, she felt a measuring cup wasn’t needed. What she had been calling “one cup” of rice had gradually grown in size. She was easily having 11⁄3 to 1-1/2 cups, thinking it was just a cup. Inaccuracies in carb counting meant she wasn’t getting the right doses of insulin.

Coral implemented some carb-counting tips and returned for follow-up three months later. Her blood-glucose levels had improved and were more predictable, so she felt safer and more confident. She explored how to further hone accuracy with a food scale, and identified apps and online resources to count the carbs in mixed dishes and ethnic foods.