Again, CGMs track and graph glucose values every 1 to 5 minutes, so the post-meal peak will not be missed, and it is easy to measure the net rise from pre- to post-meal. Perhaps the best part of using a personal CGM is being able to see, in real-time, exactly how different foods and activities influence glucose levels, and learn from the experience. For example, the user can see how high their glucose rises after different types of foods are eaten at different times of the day. 

Real-Time Continuous Glucose Monitors   Allow tracking of post-meal trends Users see cause/effect relationships in real-time

 

CGMS Case Study

Here is an example from my own personal experience, more than 20 years ago.  Note the near-normal premeal values followed by peaks near 200 mg/dl. This data from a 37 year old man with an insulin pump.

In this example, a young girl’s glucose (8 years old on glargine/MDI) is in the mid-100s before meals, but peaks near 300 after each meal.

Even in patients with type-2 diabetes, post-meal peaks can be easily detected with CGM. In this example, a 60 year old woman on oral meds shows her fasting glucose and pre-lunch glucose is perfectly normal, but her glucose rises to the mid-200s right after breakfast. If only fingersticks were performed, she would have no idea that hyperglycemia was taking place between breakfast and lunch.