Continuous Glucose Monitoring and Glycemic Control in an Adult Without Diabetes: Over 4,000 Automated Recordings Guide Contingency-Shaped Learning

The role of continuous glucose monitoring (CGM) in glycemic control among individuals without diabetes is not well understood. Specifically, the feedback generated may serve as a promising technology for obesity and lifestyle management among people without diabetes. In this case study, we used a CGM system to continuously measure sensor glucose levels in an adult female with BMI >30 without diabetes, capturing over 4,000 automated sensor recordings. The participant received real-time glucose readings via a smartphone app, which displayed values in a line graph. A shaded area indicated glucose levels exceeding the upper normoglycemic range, and an audio alert was triggered for high excursions (>140 mg/dL). We analyzed the percentage of daily time out of range (%TOR) across 16 days and evaluated whether standalone CGM feedback could reduce %TOR over the wear period. The participant reported checking the app multiple times per day every day. A notable reduction in average daily %TOR was observed, decreasing from 9.2% in the first sensor phase to 1.9% in the second. The median daily number of high-glucose excursions declined from 1.5 to 0.0. These findings suggest that standalone CGM offers feedback associated with glycemic control and can bring daily %TOR to under the recommended target of 5% in an individual with a metabolic risk but without diabetes. CGM may play a key role in obesity and lifestyle management by linking glucose tracking with behavior modification strategies, amplifying feedback necessary for contingency-shaped problem solving.