Exploring Continuous Glucose Monitors: Are They Worth It For Non-Diabetics?
The surprising and expected insights I've gained from a month of using a CGM.
Increasingly, people without diabetes are using continuous glucose monitors (CGMs) to gain valuable insights into their diets and overall health. Instead of just getting an imperfect snapshot of metabolic health from an annual blood test, they are opting for real-time, personalized data showing how their body reacts to their meals and lifestyle choices. The direct feedback can provide eye-opening insights into metabolic health. Seemingly innocuous foods or simple movements can have a huge impact on blood glucose levels. By understanding these reactions, individuals can make more informed decisions to optimize their health and well-being.
A Wake-Up Call From My Doctor
Not too long ago, I got a stern talk from my doctor after an annual blood test that showed my HbA1c was hair-splittingly close to classifying me as pre-diabetic. My doctor left me with the advice that I should eat less sugar. If you know me, you know that I’m a walking paradox: a health enthusiast who exercises most days, constantly reads the latest research to improve healthspan, loves cold plunges, cares deeply about cancer prevention, and has an enormous candy addiction that puts any child on Halloween to shame.
I've had a sugar addiction for as long as I can remember and believed my other lifestyle choices were (hopefully) negating its effects on my body. However, at 30 years old, my doctor pointed out otherwise.
Discovering Continuous Glucose Monitors
I had heard that CGMs were useful tools for understanding how certain foods and lifestyle choices contribute to growing insulin resistance. I was curious to see how much candy was actually skyrocketing my blood glucose levels and wanted to see if the Hawthorne Effect would curb my sugar intake, thus improving my HbA1C. After researching different options, I purchased a CGM from a company called Signos.
My Experience Using a CGM
What I learned after a month of using a CGM was eye-opening. There were both surprising and expected results from having direct insight into my blood glucose levels. In this article, I’ll share what I learned, my experience using Signos, how other CGM companies compare, and tips to consider for stabilizing your own blood glucose levels.
What is a CGM?
A CGM (continuous glucose monitor) is a wearable device, roughly the size of a quarter, that tracks your glucose (blood sugar) levels throughout the day, providing readings every few minutes. This data is automatically sent to your smartphone via Bluetooth, offering comprehensive insights into your blood glucose levels.
A recorded spike from my Signos app
Why Monitor Glucose Levels if You Don’t Have Diabetes?
A CGM is one of the most powerful technologies available for alerting us to early metabolic dysfunction and promoting accountability. One of the early hallmarks of metabolic disease is insulin resistance (IR) and loss of glycemic control, which can precede type 2 diabetes by 10 to 15 years. A study from Stanford found that even among people considered healthy by standard glucose ranges, 25% of them showed severe glucose variability based on CGM data, and the percentage of that time spent in severe variability patterns correlated with worse metabolic markers.
In a metabolically healthy person, a dose-dependent amount of insulin is secreted, meaning that a higher elevation in blood glucose will stimulate a higher secretion of insulin. Insulin resistance occurs when frequent blood sugar spikes cause pancreatic beta cells to release insulin repeatedly. Over time, your cells become numb to insulin's signaling, resulting in consistently higher blood sugar levels and increased risks for various health issues, including weight gain, cardiovascular disease, diabetes, and even cancer.
Insulin resistance occurs when frequent blood sugar spikes cause your pancreatic beta cells to release insulin repeatedly. Over time, your cells become numb to insulin's signaling, resulting in consistently higher blood sugar levels and increased risks for various health issues, including weight gain, cardiovascular disease, and even cancer.
Frequent glucose spikes can lead to insulin resistance, while blood sugar crashes can cause fatigue, depression, and anxiety. Over time, glucose variability can harm tissues and endothelial function more than stable elevated glucose levels. By maintaining low glucose variability, you can enhance insulin sensitivity and markedly improving health outcomes.
Factors Affecting Glucose Levels
Food significantly influences glucose levels, but it's not the only factor. The CDC identifies several other elements that I was surprised to learn can impact glucose:
Lack of Sleep: Poor sleep can reduce insulin effectiveness.
Coffee: Some individuals are sensitive to caffeine, affecting their glucose levels.
Dehydration: Low water levels can concentrate glucose.
Exercise: Different exercises affect glucose levels differently; some lower it while others, like high-intensity workouts, may raise it.
Skipping Breakfast: This can lead to higher glucose levels after later meals.
Stress: Emotional stress can elevate blood sugar levels.
Unexpected Learnings from My CGM Journey
The Hawthorne Effect Works: In the first two weeks, I continued indulging in my favorite treats like candy, donuts, and ice cream to see their impact on my blood glucose levels. After one candy binge, my blood glucose levels spiked dramatically, making me feel guilty about the strain I was putting on my body. It felt like being a messy teenager with my body constantly cleaning up the chaos. This visual feedback made me more mindful, and I naturally started avoiding foods that caused significant spikes. This was the most powerful and welcome result from wearing my CGM.
First 24 Hours Can Be Unpredictable: I followed the best practices for applying the sensor when blood glucose levels are stable, but my readings were erratic during the first day. At one point, my blood glucose dropped to 40 mg/dL, far below the normal range of 80-120 mg/dL. Worried, I contacted the Signos support team, who explained that it can take up to 24 hours for the sensor to calibrate, and readings can be unusual during this period. After 24 hours, my readings stabilized, but I lost a day of accurate data, reducing the effective lifespan of the sensor to 9 days out of 10.
CGM Application Takes Some Courage: Despite hearing that applying the CGM sensor was completely pain-free, I was taken aback when I saw the needle—it was much longer than I anticipated, and I’m terrified of needles! My confidence wavered, and I had to ask my husband to apply the sensor to the back of my arm. The sound it made was more intimidating than the sensation itself, which was pain-free.
Some Normal Foods Cause Spikes Too: White rice caused a massive spike in my blood glucose levels, close to eating a bag of candy. Even paired with salmon and seaweed, the white rice in my poke bowl caused a 56-point spike, and my levels stayed high for a while. This is one of the main benefits of wearing a CGM - learning your reaction to individual foods and meals. Different individuals respond differently to the same food depending on factors like microbiome composition, sleep, recent meals, and body type. White rice may be fine for you, but it is something I will have to eat sparingly.
Walking After Meals Is a Game Changer: Taking a walk after meals made a huge difference in curbing blood sugar spikes. On average, my blood glucose level dropped by 26 points after a 20-minute walk. This is probably why walking is often called one of the best medicines for your health.
Companies Offering CGMs for Non-Diabetics
Until recently, a prescription from a medical care professional was required to get a CGM, but in March 2024, the FDA cleared the first over-the-counter CGM in the U.S. (Dexcom Stelo)A variety of different CGM programs have emerged to help provide more insight into metabolic health and help anyone take a more proactive role in keeping an eye on their blood glucose levels. Generally, each company provides you with the sensors that will approximate your glucose levels, an app where you can track your food intake and see your glucose levels, view additional health insights, and get support from a certified nutritionist. Currently, there are three main companies in the CGM market.
1. Signos
Signos takes a weight-loss angle compared to the other CGM companies, stating a mission to tackle the obesity epidemic. They do so by providing insights and notifications that can help people stabilize their glucose levels and therefore lose weight. One of the main benefits of Signos is that it is more affordable than other options if you want to use it for a shorter period of time, which is why I went with Signos. The 3 month plan is currently $549.
Drawbacks to Signos
I found the app to be unintuitive and lacking in sophistication. The food logging feature has a lot of ground to cover before reaching the capabilities of apps like Coronmeter or MyFitnessPal, so I found myself just taking pictures of my meals in Signos and tracking my macros in other apps. Lastly, when comparing Nutrisense vs. Signos, Signos has limited nutritionist support that may not include customized plans, guidance, and motivational coaching.
2. Nutrisense
Nutrisense also offers flexible CGM program options from one month, three months, six months, or one year. Members will also start working with a nutritionist on day one to set goals, understand biodata, and develop a totally custom health plan. Their 3 month plan currently costs $897.
Drawbacks to Nutrisense
To collect all of your CGM data, members will need to scan their sensor using the Nutrisense app every eight hours. At this time, Nutrisense is only available in the United States.
3. Levels
Levels has probably been around the longest, and offers a suite of services. Members can access a nutritionist marketplace for added support from qualified nutritionists and members can add on blood panels in order to get a more comprehensive look at their health. Like other programs, Levels offers short and long term plan options but their pricing system is set up a little differently, with app and membership fees.
Drawbacks to Levels
Levels is one of the more expensive options on the market today, and I find their pricing model to be very confusing. However, it does come with a more built-out app and a suite of services you can use to round out your health insights.
Should You Get a CGM? My Final Thoughts
Although glucose variability is probably one of the most important metrics for healthspan, focusing on just one metric can still lead to unhealthy decisions. For example, you could probably eat only diet soda, bacon, and cheese and keep your blood glucose levels relatively in check. Healthy glucose variability doesn’t necessarily mean you are eating enough food, or getting sufficient exercise, fiber, or protein. However, I realize most people are probably not in range of healthy glucose variability. If it is financially feasible, using a CGM for a couple of months can provide the necessary wake-up call and accountability needed to take action and improve overall health.
With that being said, the changes you may need to implement to take control of your metabolic health will probably come as no surprise:
Sleep: Get honest about your sleep habits and get plenty of sleep every night
Stress: Manage your stress with meditation, outdoor activities, and social interactions
Cut: Processed foods (anything that has an ingredient that would not be in your kitchen) and alcohol. Truly, no amount is a safe amount.
Eat: Balanced meals complete with protein, fiber, anti-oxidants, and healthy fats
Exercise: Walk often and preferably right after a meal. Strength train 3x a week to improve muscle mass
Drink: Plenty of water every day