Catching Carb Peaks (When To Test Blood Glucose)

CONCLUSION: To best assess peak postprandial glucose levels, the optimal time for blood glucose monitoring is about 1h and 15 min after the start of the meal, albeit with wide interpatient variability. Nevertheless, 80% of post-meal blood glucose peaks were observed at less than 90 min after the start of the meal.

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That’s really interesting. @britt_j, do you have access to the full article? Are they assuming while taking insulin, or without insulin? I figure the results might be different.

If it is with insulin, it would be pretty cool for us – and easy – to look back and see how true that is for us.

They used CGM data, and everyone was using insulin.


For this retrospective analysis, 69 ambulatory continuous glucose-monitoring system (CGMS) profiles were obtained from 75 consecutive insulin-treated patients with diabetes. The parameters measured were the peak post-meal blood glucose values, peak time, and rates of increase and decrease to and from the zenith of the resulting curves.

The mean peak time after breakfast was 72+/-23 min, which was reached in less than 90 min in 80% of the patients. The apparent glucose rate of increase from pre-meal to the maximum postprandial value was 1.23+/-0.76 mg/dL/min, while the glucose rate of decrease was 0.82+/-0.70 mg/dL/min. Peak time correlated with the amplitude of postprandial excursions, but not with the peak glucose value. Also, peak times were similar after breakfast, lunch and dinner, and in type 1 and type 2 diabetic patients.

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I find this a bit curious. It looks like it was from 2010, and was using CGM instead of BG readings. Not really a good metric back then.

Finding peak time and using CGM instead of BG tests?