What I learned during my first week with a continuous glucose monitor (CGM)

About a week ago, I got started with a continuous glucose monitor. "Glucose monitor" means it's a device that records and reports blood sugar. "Continuous" means it is collecting data throughout the day and night.
 
You might be wondering:

Why? Are you diabetic or pre-diabetic? 

No, thankfully I am not!

However, data is growing showing a link between metabolic health and many major diseases, from the more well-known links like heart disease to the lesser-obvious ones like dementia and certain types of cancer. I want to reduce my risk for these chronic diseases and also increase my likelihood of being able to continue the types of activities that I enjoy. This is one part of broader habits meant to benefit my health (e.g. good sleep habits, healthy eating, mental & physical exercise, stress management, etc.).

But can't you just eat keto or vegan or whatever my preferred diet is?
 
Turns out there can be great difference in people's genetics and biomes, leading to different responses to different foods. I have some simple eating habits that help me a great deal, but one reason I'm doing this is to see what is healthiest for me.

About the CGM:

I acquired my CGM through Levels, as part of their beta. They do not manufacture the CGM device, but instead make an app and service that works with the CGM data.
The CGM is applied to the upper arm and stays there for up to 14 days. It's held on by an adhesive patch. While there, it records and holds up 8 hours worth of data. A mobile phone is held up to the CGM to pull in the data to the CGM manufacturer's default app.
Levels has developed an additional app and service that enhances the base data from the CGM manufacturer. It links with Apple Health data and the CGM app data to perform enhanced reporting.
The Levels app takes my notes about food/drink, exercise, or other events (like stressors) and uses these data points to score those actions by looking at the blood sugar for the 2 hours following the activity (they call this a "zone"). Zones are scored 1-10 based on blood sugar response. Days also get a rating of 1-100, and then daily, weekly, (and it looks like) monthly reports are provided. 

The three main scoring factors Levels uses are:

  • Glucose Variability (lower scores better)
  • Average Glucose (lower scores better)
  • Time in Target (higher is better, with "target" being 70-110 mg/dL)

The app also builds a catalog of zone scores so that I start to get a profile of healthier activities (10/9/8) and less healthy ones, based on my unique metabolism. It also offers "challenges" of things to try different ways to see what my scores will be, to help me make informed decisions.

What I've Learned:

  • Mornings must start right: I see that my days often start on my higher end for blood sugar. In addition, if I have carbs in the morning, it is easier to spike. Prevailing wisdom about this is that our bodies are ramping up cortisol in the morning as we prep for the day (and perhaps start experiencing stressors). One of my friends who is a doctor said this cortisol response is why many heart attacks happen in the early morning! What I've learned is I should skip breakfast, have a very-low (or no-carb) breakfast, or have a mild workout and then have a light-carb breakfast.
  • Exercise makes even more difference than I thought: I already knew that taking a walk after a meal is helpful, but I didn't realize just how much. I had a pretty terrible dinner one night (pizza, sport drink, cake, ice cream), and some fun exercise before and afterwards, and my blood sugar wasn't too bad! Conversely (see bullet #1), I've had morning meals that registered as really bad (a #3 score), even when they didn't include sweets.
  • Order of operations - not just for math: what order I have my meal in makes a difference. Putting the fiber, fat, and protein at the front of a meal leads to better results than having bread, etc. up front. If there's something a little bad in the meal, having it last really does help. This is likely because the absorption rate of carbs is slowed down by the fiber, fat, and protein.
  • Ice cream isn't so bad: Likely a corollary of the above bullet, ice cream doesn't affect my blood sugar too much. This may be my best option when having an occasional treat.

I'm looking to see what I learn about more food, exercise, and stressor events in the coming weeks. Which food pairings work for me and which do not? Does meditation counteract stressors sufficiently? Do I do ok with sweet potatoes? Bananas? Rice? Much more to learn!

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Have you used a CGM? Do you have questions for me or ideas for experiments? I'd love to hear from you.
Todd Grotenhuis @toddgrotenhuis