Qualy #26 - What is Peter looking to achieve and monitor with his blood glucose monitor?
The host discusses using continuous glucose monitors (CGM) and the Oura Ring as powerful behavioral tools. He details how CGMs aid diet management and calibrating activity to minimize glucose spikes, preferring CGM data over A1C for metabolic health.
Deep Dive Analysis
9 Topic Outline
Personal Use and Benefits of Continuous Glucose Monitors (CGM)
CGM as a Powerful Behavioral Tool
Calibrating Activity and Diet with CGM Feedback
Challenges and Future of Consumer-Grade CGMs
Why Continuous Insulin Monitors Don't Exist
Understanding Glucose Variability from CGM Data
Critique of Hemoglobin A1c (HbA1c) as a Metric
Impact of Beta-Thalassemia Trait on A1c Readings
The Future of CGM Replacing A1c
5 Key Concepts
Continuous Glucose Monitor (CGM)
A device that provides real-time feedback on blood glucose levels. It serves as a powerful behavioral tool, helping individuals control their diet and activity by showing immediate glucose responses to food and exercise, similar to an RPM tack in a race car.
Glucose Variability
Measured by the standard deviation of glucose levels, it indicates how much blood glucose fluctuates throughout the day. High variability suggests different insulin profiles compared to low variability, even if average glucose levels are the same, making it a crucial metric alongside average glucose.
Hemoglobin A1c (HbA1c)
A blood test that measures average blood glucose levels over the past 90 to 120 days, based on the lifespan of red blood cells. However, its accuracy is compromised if a person's red blood cell lifespan deviates from this assumption, leading to potential over or underestimation of average glucose.
Radioimmune Assay (RIA) / ELISAs
These are laboratory methods used to measure insulin levels, which involve multiple steps like adding enzymes and rinsing. Because they cannot yield an answer quickly without washing, they are not suitable for real-time, point-of-care continuous insulin monitoring devices.
Beta-Thalassemia Trait
A genetic condition that affects red blood cells, causing them to live longer than the typical 90-120 days. For individuals with this trait, the Hemoglobin A1c test will artificially read higher than their actual average glucose, leading to a misclassification (e.g., as pre-diabetic).
5 Questions Answered
Peter Attia uses a CGM primarily for behavioral control, as it provides immediate feedback on glucose spikes, which motivates him to make better food choices. It also helps him calibrate how activity levels, nutrient deprivation, and treats affect his glucose, minimizing potential damage.
Continuous insulin monitors are not currently feasible because insulin measurement assays (like radioimmune assays or ELISAs) require multi-step chemical reactions that cannot be performed quickly enough for real-time, point-of-care devices.
CGM directly measures and reports average glucose and glucose standard deviation, which are the most relevant metrics. HbA1c, on the other hand, imputes average glucose based on an assumption about red blood cell lifespan, which can lead to inaccuracies.
The primary limitation of HbA1c is its reliance on the assumption that red blood cells live for 90 to 120 days. Any condition that alters red blood cell lifespan, such as beta-thalassemia trait, can lead to an over or underestimation of actual average glucose levels.
Glucose variability, measured by standard deviation, is highly relevant to insulin profiles. Two individuals could have the same average glucose, but one with low variability and another with high variability would indicate very different underlying insulin dynamics.
7 Actionable Insights
1. Use CGM for Behavioral Control
Employ a continuous glucose monitor (CGM) as a powerful behavioral tool to avoid glucose spikes, especially if you are internally competitive, as seeing the data can deter unhealthy food choices.
2. Pre-Treat Fasting & Exercise
To minimize the negative impact of treats like fries, consider fasting all day and working out beforehand, as this strategy can help prevent a significant glucose spike.
3. Monitor Glucose Variability
Use a continuous glucose monitor (CGM) to track your glucose levels and, importantly, your glucose standard deviation (variability), aiming to keep variability low as a proxy for healthy insulin levels.
4. Consider Wearable Health Tech
Explore using a Dexcom G6 Continuous Glucose Monitor and an Oura Ring, as these are highlighted as ‘sticky’ wearables that provide valuable real-time data and are hard to stop wearing once adopted.
5. Request CGM Prescription
If interested in continuous glucose monitoring for health insights, consider asking your doctor for a prescription for a medical-grade CGM like the Dexcom G6.
6. Question A1C Reliability
Be aware that hemoglobin A1C can be an unreliable measure of average glucose due to factors affecting red blood cell lifespan, and it doesn’t provide insights into glucose variability.
7. Embrace Feedback Mechanisms
Recognize that humans are ‘feedback machines’ and need data to perform optimally, suggesting the importance of seeking and utilizing feedback in various aspects of life, much like a race car driver needs an RPM tachometer.
3 Key Quotes
There is no more powerful behavioral tool for me than my cgm because in the end I'm kind of a competitive person internally much more competitive internally than externally by the way and I just can't stand to see spikes of glucose it just drives me nuts.
Peter Attia
I don't know that I could drive a race car very well without seeing my rpm tack like if you plugged my ears so that I couldn't actually hear the rev of the engine and you took away my rpm tack and said drive could I still drive the car yes could I drive it half as well as I can drive it when I know exactly where I'm shifting at every moment where I need to shift no there's simply no way like we just we're feedback machines we need feedback.
Peter Attia
My hope is that in 10 years maybe that's ambitious I would hope that the hemoglobin a1c can't even be ordered on a lab and everyone just has a cgm.
Peter Attia