Why I Tried CGM During My Real, Busy Life
I love nutrition, food science, and experiments…so when I was given the opportunity to trial a continuous glucose monitoring system for a month, I said yes! I wanted to know what continuous glucose monitoring (CGM) revealed about my normal eating patterns over a two-week period, with the intention of making changes in the latter two weeks.
I’ve always been interested in data and health experiments. Over the years, I’ve:
- Tracked activity with Fitbit since 2014
- Participated in bone density research
- Completed a VO₂ max study (measure of cardiovascular fitness and aerobic endurance)
- Contributed to endometriosis biomarker research (NextGen Jane)
- Used finger-stick glucose monitoring during and after pregnancy
Before I share what I learned, here’s what a continuous glucose monitor actually does.
Quick Overview of a CGM System:
A CGM system is a device that continuously monitors blood glucose levels through a sensor placed just under the skin (often in the arm) and wirelessly transmits readings to a device (or an app on your phone) every 5 to 15 minutes. You change out the waterproof sensor every 15 days.
Why Glucose Levels Matter?
Glucose readings can give you more insight into how your body responds to food, drinks, caffeine, sleep, physical activity, and other factors.
You may be familiar with hemoglobin A1C (HbA1C), a one-time lab test that provides an average blood sugar level over the past 2-3 months and is considered the gold standard for monitoring diabetes risk and other related health conditions.
A CGM gives you more details on short-term glucose variability (or how much your blood glucose levels fluctuate) within a specific range. CGMs are relatively new, first approved for use in people with diabetes in 1999, and expanded to people without diabetes without a prescription in 2024. With CGMs more readily available, research indicates that higher glucose variability (spikes) over time can lead to type 2 diabetes, heart disease, whole-body inflammation and stress, leading to vascular damage.
In general, the goals set by the CGM app are to:
- Maintain a glucose variability percentage below 15% (which indicates how many and the height of the glucose spikes and dips) = glucose stability
- Have minimal spikes (quick-rising blood glucose levels), this system recommends less than 2 per day
- Stay within the predetermined glucose range for 85-100% of the time
- Prevent late evening blood glucose spikes
How does Anti-Inflammatory Eating Connect?
A CGM is just one tool to assess how your body responds to various factors, including eating, meal combinations, exercise, and more. Blood glucose spikes can trigger pro-inflammatory states in the body.
Choosing anti-inflammatory foods and helping to maintain steady blood glucose levels can help reduce inflammation in the body and prevent future diseases.
Eating balanced meals also helps you to feel your best each day. When I eat well, I can think clearly, work more efficiently, and my mood is more stable. All things that benefit myself and those around me.
So, what actually happened when I wore the CGM for two weeks without changing anything?
What Did The First Two Weeks Reveal About My Normal Routine?
I “knew” some of my eating patterns or behaviors were not supporting my overall health. However, seeing the data was eye-opening (and motivating).
Dip Trend: Coffee Without Breakfast
I’ve developed an unsupportive habit of drinking coffee before eating over the past several months. I drink about 1.5 cups of coffee with a splash of half-and-half, no sugar, but I am really sensitive to caffeine and knew this was not a helpful choice to start my morning.
However, seeing on the app that my blood sugar was in the 70-80s was an eye-opener to why I felt so jittery, anxious, and overstimulated during the first hours of each day. Even if I ate a balanced meal within 30-45 minutes after the coffee, I didn’t feel like my usual self for several hours, and my blood sugar returned quickly to 70-80s (indicating I probably needed to eat more).
So I only let this coffee before breakfast experiment play out for 2-3 days. I had experienced it for several months, but didn’t need two weeks to support it further. It was important for me to be in a better state while getting my kids ready for school and having a positive morning with them. Plus, when it was time for my brain to start working, I was ready, not waiting for it to warm up still.
Since switching to a high-protein and fiber breakfast, that caffeine doesn’t impact me negatively, I can think clearly, and am no longer jittery or anxious feeling in the morning. And I didn’t have to give up coffee – just change the way I enjoy it. My blood sugar is now within the 80-100 range a few hours after eating, which I feel better at.
Spike Trend #1: Snacking Before Bed
I tend to work for a few hours after my kid’s bedtime a few nights a week, and after I finish working, I gravitate towards a snack (even if I am not hungry). Often I choose an apple with peanut butter, cheese and crackers, or carrots and hummus, which did not spike my levels.
However, twice I had foods that reflected more than hunger: sea salt and vinegar potato chips or French fries.
As a dietitian, I know that a carbohydrate by itself (some people refer to these as “naked carbs”) is not a great choice because it can quickly spike blood sugar levels (and then they quickly fall, leaving you feeling hungry again) and doesn’t provide sustained energy. I gravitate toward simple carbohydrates (potatoes) when I am too tired or emotionally spent.
The chips and French fries spiked my blood sugar for several hours, and it remained in the higher range all night while I was sleeping, and I woke up not hungry (making it harder to eat before coffee).
For optimal sustained energy, choosing a protein, fiber, and fiber-rich carbohydrate as a snack at least one hour before bed is a better choice. Protein and fiber slow down the absorption of carbohydrates, leading to a slower rise and fall in blood glucose levels. Pairing chips or French fries with a protein and fiber option would be an improvement!
Spike Trend #2: Eating A Meal and No Movement
I move often throughout the day. After meals, I tend to get up and do something (like doing the dishes, laundry, taking a walk, or playing a Nerf blaster game, etc.). I didn’t realize how beneficial this was for blood glucose stability until the CGM caught my spikes a few times after I sat down after a meal (usually in social settings where we sat and talked after the meal for a longer period of time).
Interestingly, I’d eaten these exact meals (Beef Vegetable Stew and Chicken Tortilla Soup) and didn’t have a spike, but I did spike when I sat for one to two hours after the meal.
Research shows that small bursts of movement throughout your day is beneficial for health, mood, reduced snacking, blood glucose control, and a lower risk of developing high blood pressure and heart disease.
For blood glucose control, research indicates that 2 to 3 minutes of light or moderate walking every 20 to 30 minutes can lower glucose and insulin levels after meals by approximately 15-30%.
For reference, Halloween, trick-or-treating, and candy fell into this category. We walked a LOT (2.75 miles) on Halloween after dinner. The houses in our neighborhood are spaced far apart from one another. My blood sugar levels remained stable while I walked and ate a few pieces of simple carbohydrate candy (with no protein or fiber). However, we got home, and I had three more mini-pieces while my kids sorted their candy. And predictably, my blood sugar spiked and went back down quickly.
I wouldn’t change the Halloween night behavior, as it’s not my norm; it’s good to enjoy sweets and candy in moderation. Being too rigid with eating and meals can also be detrimental to your health and what you model to those around you. For extra resources on eating a balance of foods (including sweets) and developing a healthy mindset, hop over to the Ellyn Satter Institute for more tips on “developing a positive and joyful relationship with food.”
For most meals and days, it’s helpful to remember that movement helps you feel energized and control post-meal glucose levels. Even micro-movement (cleaning up after dinner, laundry, a 2 2-minute walk, or walking up and down your stairs) can keep those numbers stable.
You don’t need a CGM to benefit from these strategies. Most of the positive habits I reinforced—such as eating balanced meals, engaging in movement after eating, and avoiding late-night simple carbs—are foundational principles that anyone can adopt without relying on technology.
The CGM helped me connect actions to immediate results (balanced meals = sustained energy for several hours vs. simple carbohydrates or waiting to eat breakfast = less energy, focus, and a need to eat again sooner). I know these things, but it was a helpful reinforcement for me.
Takeaways
My biggest takeaway from this experience is that the fundamentals matter more than any single food or meal. Balanced meals with protein and fiber, eating regularly, and engaging in light movement after meals helped keep my glucose stable and my energy steady.
And while the CGM was insightful, you don’t need one to benefit from these habits. These are anti-inflammatory, blood-sugar-friendly principles anyone can practice with or without technology.
For me personally, the two most impactful changes were:
- Eating a protein and fiber-rich breakfast before coffee
- Choosing a protein-fiber combo instead of simple carbs late at night
For the second half of the month, I plan to see if removing my evening or bedtime snack helps me have more of an appetite in the morning. Since I got into the habit of skipping breakfast or postponing it until later in the morning, my appetite is now smaller in the morning.
However, if I want to feel energized (and avoid jitters from drinking coffee), a balanced breakfast is essential for me. And I do want to continue enjoying coffee in the morning. I have also moved my 30-minute walk to the morning, before my kids wake up, to help our 11-month-old Labrador puppy burn off some of her endless energy. Therefore, an energizing breakfast when I return is essential.
Technology can be a helpful feedback tool—but healthy habits are still the foundation. Read a past article of mine on how to design meals with anti-inflammatory foods and learn to use the plate method to balance nutrients and fuel your body optimally.
You might also be interested in 11 Healthy and Easy Lunch Ideas to Stay Energized or my free Printable Anti-Inflammatory Diet Food Lists (PDF Download) to help you with your next shopping trip.
Let’s get UNstuck and stay UNstuck!