Getting Started with Continuous Glucose Monitoring
Turns out, exercise won't fix prediabetes alone.
I stole my wife’s Christmas present.
One of our best friends tried out Levels to track her blood glucose. She told us all about how excited she was to find out which traditionally-defined “health” foods would affect her. My wife was intrigued. I was not.
.
On top of Levels being out of my price appetite1, I just wasn’t all that into the idea of a continuous glucose monitor (CGM). “It won’t show if what I’m eating is healthy, right? Like I could just eat bacon all the time and not spike it,” I thought.
My wife looked into Levels, had the same feelings about price as I did, but wondered about her CGM results. She ended up asking for the Stelo CGM for Christmas. Her mom Santa brought her a two pack. She plugged it in, showed me the results, and after a day I thought “huh, I should really try that.”
She agreed.
Right after my youngest was born last year, I got a blood test that showed I had prediabetes. I hadn’t really changed my diet that much since then — I’ve mostly relied on running. I assumed that exercise was the path to enlightenment and ultimately health. That journey led me to running over 500 miles last year. That’s not a lot for the runners out there (I see you, 3000 milers, you), but it was a meaningful life change for me. I was even able to recently run a sub-22 min 5k, a feat I’m proud of. Prior to the CGM, I thought I had my prediabetes under control due to my aerobic fitness. I no longer think that.
Disclosure: I’m no health expert. I’m just a dad in my 30s trying to share what he learns along the way. Please do your own research and talk to your doctor prior to starting any health program.
How does a CGM work?
A CGM works by inserting a small, painless needle-thing under the skin. The CGM doesn’t connect straight to your blood cells, but rather looks at the interstitial fluid around the cells. According to the Cleveland Clinic, this fluid leaks out of your blood capillaries and contains glucose, aka sugar2. The CGM picks up on these levels, and relays that information to your phone.
In my case, the Stelo app picks up that data and displays the information in a chart. Stelo gives you a range of blood glucose levels to shoot for. By default, that range is 70–140 mg/dL. I’m honestly not sure what the metric means. But I do know higher is worse, and lower is generally better, as long as you’re in the range.
My CGM results
Three of my closest humans (wife and two best friends) also have CGMs. We eat meals together ~4-6 times a week. After each meal, my spikes are almost always worse than theirs. My spikes are higher, they last longer, and my blood glucose typically stays higher after we’re finished.
Granted, we’re not bastions of fitness. None of us are “athletes” in the true sense of the word. We’re all on our own health journeys, but none of us are that far down that journey path. I say this to highlight that I’m not comparing myself to some professional fitness influencer. These are my people. We live similar lifestyles. On paper, our insulin sensitivity should be relatively similar. It isn’t. Mine is worse.
Which means I need to be even more mindful of what to put in my body.
My prediabetic status indicates (and my recent CGM usage proves) that my body can’t use the insulin it produces to regulate my blood sugar. As a result, my blood glucose will be higher than my friends or even the average person.
I’m almost positive that prior to getting a CGM, I was unknowingly putting my blood glucose way above the range on a daily basis. My time in range (or TIR in some studies) would have been less than 50%, I think, which is horrible.
Getting in the (Food) Arena
My knowledge about foods affecting my body has moved from an academic mindset (example: “yeah I know processed foods are generally bad”) to a practicing one (“I know foods X, Y, Z will spike my blood glucose levels in the morning”). The CGM has changed my mindset around food
Just like my friend responded to me when I was complaining that a small bowl of cocoa pebbles spiked my blood glucose: “you can’t unknow what you know now.”
So far, what I’ve learned is that my body can only process carbs in a “safe” way if I have more grams of proteins than I have of fats. For example, if I have a half a cup of rice, plain, my glucose level will spike. But if I have that same amount of rice with a whole chicken breast, then there’s no spike. This rule seems to apply for every meal that I’ve had. TL;DR? The more protein, the better.
The Scale lies
I used to think of myself as a black hole for calories. I’ve been lucky enough to never have serious weight issues. My weight right now is within 5 lbs of where I was in high school. Minus a few months in the 190s after the births of each of my kids, I’ve been in the 170s my entire life.
Turns out, weight is actually a horrible health metric3. My weight has lulled me into a “yeah I’m fairly healthy” mentality. The CGM has ripped that innocence from me in the best possible way. I can no longer go about my life thinking that I am a black hole. It sounds silly, but I know with 100% certainty now that cocoa pebbles are just sugar cardboard that my body doesn’t know what to do with.
Would I recommend a CGM?
Generally, yes, yes I would. Even for non-diabetic, or non-prediabetic people. I believe most people could benefit from learning how their body reacts to different foods. I would not recommend it for someone who has had or is likely to develop an eating disorder, however. The level of CGM tracking could get addicting, as well as feelings of “my blood sugar is high, therefore I’m a bad person.” I also would not recommend it if you’re looking for a passive way to improve your health. A CGM’s insights are useless if you’re not going to do something with them.
— Stevo
At the time of this writing, Levels is $392 for a year-long subscription. Included is their app, which helps you log the food you eat; and a month of CGMs, delivered quarterly. They somehow are able to give you the Dexcom G7, Dexcom’s most accurate CGM that typically requires a subscription. It’s honestly not that expensive for what you get, I just wasn’t ready to spend $400 bucks. yet.
For more on how CGMs work, see the Cleveland Clinic’s article on CGMs.
I recently wrote about BMI and my own body composition here: Fat-Free Mass Index (FFMI): What it is, why it matters, and why is mine so low? The TL;DR is that BMI doesn’t tell you what your body is made of. If you only rely on your weight to tell you if you’re healthy or not, you’re not getting the full picture.