I knew about blood sugar long before I became a nutrition counselor.
Some of my early memories involve sitting at my Nana’s kitchen table, watching as she pricked her finger, gently squeezed out a drop of blood, and placed it onto her glucometer. I would wait for the number to appear and ask, “Is that good?” Sometimes she would give herself insulin. Other times, she’d pour a small glass of juice. Even as a child, I understood that the number mattered.
My Nana and my father became insulin-dependent diabetics in their late 30’s and early 40’s. Many other family members on that side now show signs of prediabetes. In our family, diabetes has shown up as what’s called Type 1.5 diabetes, or Latent Autoimmune Diabetes in Adults (LADA), an autoimmune condition in which the immune system slowly attacks insulin-producing cells. It appears later in life like Type 2 diabetes, but is autoimmune like Type 1.
Observing My Own Blood Sugar
While I was in college and just beginning to take an interest in nutrition, I visited my grandparents in Florida and asked my Nana to check my blood sugar while she was checking her own. We had recently snacked on nuts and dates. I don’t remember the exact number, but I do remember her reaction. She was alarmed that mine was so high and insisted we stay home until she could retest it and see that it came back down — which it did.
For a long time after that, blood sugar stayed mostly in the background of my own health story. During pregnancy, I was admittedly nervous about the oral glucose tolerance test, given my family history and being in my 30’s, but mine was normal. I took that as reassurance that the attention I paid to diet and lifestyle was making a difference.
It wasn’t until after my daughter was born, when I was diagnosed with Hashimoto’s and struggled with significant adrenal dysregulation, that blood sugar moved back into focus. I began to look more closely at the relationship between glucose, hormones, inflammation, and energy.
At the time, I did what my Nana had always done. I used a traditional glucometer. I’d eat a meal, then test my blood sugar one, two, and three hours later, comparing my numbers to what was considered a healthy range. It was the best tool we had, but it offered only snapshots.
Today, continuous glucose monitors offer something different: a way to see patterns unfold in real time. And that shift — from individual readings to observing continuously across the days and weeks — is where CGMs can be especially helpful.
What is a Continuous Glucose Monitor?
A continuous glucose monitor (CGM) is a small, wearable device that tracks glucose levels. A thin sensor is placed under the skin (usually on the back of the upper arm) using an automatic applicator. An adhesive patch holds the device, which is about the size of a nickel, comfortably in place. The CGM sends glucose readings wirelessly to a smartphone or receiver, allowing you to view your data throughout the day.
CGMs were originally developed to help people with diabetes manage blood sugar more safely and effectively. In recent years, they’ve moved into the broader wellness space, sparking curiosity among people without diabetes who want to better understand how their body responds to food, stress, sleep, and daily life.
This growing interest makes sense. Blood sugar regulation plays a role in energy, mood, focus, inflammation, and long-term metabolic health. At the same time, more data does not automatically equal better health, especially without context.
In this post, I want to take a thoughtful look at what CGMs actually measure, and when they may (and may not) be a helpful tool.
What CGMs Measure
A continuous glucose monitor measures glucose levels in the interstitial fluid, the fluid that surrounds your cells. This is different from a traditional blood glucose reading, which measures glucose directly in the bloodstream.
Because of this difference, CGMs reflect glucose with a slight delay, typically about 5–15 minutes behind blood glucose. This lag is normal and important to understand. CGMs are not designed to provide a precise, moment-by-moment blood sugar value.
Most CGMs collect data frequently – often every one to five minutes, depending on the device. Their strength lies in showing patterns and trends over time.
What CGMs Do (and Do Not) Tell You
CGMs allow you to observe how glucose rises, falls, and stabilizes throughout the day and night, how it responds after meals, and how quickly it returns toward baseline. This kind of continuous data can reveal trends that are often difficult to see on standard lab tests alone.
Importantly, CGMs also highlight influences beyond food. Sleep quality, stress, exercise, illness, and daily routines can all shape glucose patterns in ways that aren’t always obvious.
At the same time, CGMs do not measure insulin directly, and they cannot, on their own, diagnose insulin resistance, diabetes, or metabolic disease.
Glucose trends are just one piece of a much larger picture — one that includes symptoms, medical history, laboratory data, lifestyle factors, and overall health context.
Understanding Glucose Patterns
One of the most common pitfalls with CGMs is focusing too narrowly on individual spikes. While post-meal rises can be informative, isolated readings are far less meaningful than overall patterns.
A relatively steady baseline, with predictable rises and gradual returns toward baseline, is often more important than trying to avoid every increase in glucose. Some variability is normal and expected. In fact, chasing a “perfect” glucose curve can create unnecessary stress without improving health.
Post-meal responses are also highly contextual. Carbohydrates (sugars and starches) do not act in isolation. Protein, fat, fiber, portion size, timing, and even the pace of a meal all influence how glucose behaves.
The same meal can produce very different glucose responses depending on sleep quality, stress, illness, hormonal shifts, hydration, and overall nervous system state, highlighting that glucose regulation is influenced by more than just food.
When CGM data is viewed without considering these factors, it’s easy to draw conclusions that are incomplete or misleading.
When a CGM Can Be a Helpful Tool
When used thoughtfully, I believe that CGMs can be a very useful tool. They may offer meaningful insight for individuals with insulin resistance, prediabetes, or like me, a family history of metabolic disease. They can also be useful for people who experience symptoms suggestive of reactive hypoglycemia, such as shakiness, fatigue, or brain fog between meals.
In some cases, CGMs can help connect the dots between blood sugar patterns and chronic inflammation, autoimmune conditions, or digestive disorders, where glucose swings can amplify symptoms.
Used for a limited period of time, they can also serve as an educational tool, helping people better understand how their body responds to meals, stress, sleep, and daily rhythms.
The key is intention. A CGM is most useful when there is a clear question being asked, rather than a goal of constant monitoring or optimization.
When More Data May Not Be Better
CGMs are not a good fit for everyone. For individuals with a history of disordered eating, anxiety around numbers, or a tendency toward rigid food rules, continuous glucose data can quickly become overwhelming or counterproductive.
In many cases, developing trust in internal cues — hunger, fullness, energy, and overall well-being — is far more important than tracking external metrics.
Without careful framing, more data can increase stress and disconnection rather than provide insight. As with any health tool, the question isn’t just what it measures, but how that information will be used.
My Personal CGM Experience
I’ve been using a CGM for two-week periods, once or twice a year, since 2022. For me, it has been a valuable tool when used alongside my annual bloodwork and other routine monitoring.
One of the biggest takeaways for me has been how limited my previous spot-checking was — whether that was finger prick reading with a glucometer or even a single fasting glucose value from the lab.
I often joke that my blood sugar is a lot like me: it’s very sensitive and it feels everything intensely!
What I mean by that is this: I may eat a meal and see my highest glucose spike anywhere from 40 to 80 minutes afterward, but by the time I check one hour or two hours later, the spike is already on its way down. Without continuous data, that part of the story would have been easily missed.
I’ve had a similar realization around fasting glucose. I also joke that for me, it should be called a “starving” glucose! I tend to wake early and hungry, and I can see that my fasting glucose at a lab looks very different from my usual glucose patterns at home. That lab value is taken after rushing out of the house, driving to the lab, sitting in a hospital waiting room, and prolonging my breakfast. Not to mention that this testing now involves meaning and emotion for me. You see, context matters.
Wearing a CGM has also made it clear how differently the same meal can affect my glucose from one day to the next. Stress, sleep, exercise, the day of my cycle, and overall nervous system state often play as big of a role as the food itself.
The only two times my CGM alarmed for very high post-meal glucose were while I was walking from the restaurant to my car. In both cases, the temperature had dropped, I was underdressed, and I was shaking from the cold. While I was still in the restaurant, my glucose had been rising steadily, but it was the sudden cold stress that seemed to push it higher.
I’ll be honest, there have been moments when seeing my less-than-ideal glucose control has felt anxiety-provoking — especially compared to Roy’s super-stable-glucose!
At its best, using a CGM has helped me focus on patterns rather than perfection.
Without context and understanding, that data could easily become overwhelming. But used briefly and thoughtfully, it has deepened my understanding and supported more individualized decision-making. And I hope this will continue to lead to good health outcomes over time.
As I sit here writing this post with a CGM on my left arm, I think about my Nana at her kitchen table, pricking her finger and waiting for a single number to appear. The technology has changed, but the goal hasn’t. We’re both trying to observe our own bodies and understand how to intervene to best support them.
If you’re considering a CGM and want guidance on whether it’s appropriate or how to interpret the data, learn more about our nutrition services and schedule an appointment with Debbie.
