5 Reasons You Don’t Need a Continuous Glucose Monitor (CGM)
The latest trend in health and fitness is the use of Continuous Glucose Monitors (CGMs) in the general population (i.e. people without diabetes) to improve health, lose weight, and prevent chronic disease.
As with every new entry to the overflowing pool of health trends, my hope is that you are putting on your “skeptical glasses” and “critical thinking cap” and asking yourself, “Do I really need a CGM to be healthy and live longer?”, and “What is the purpose of this post/ad - is it trying to educate me, or sell me something?”
It is my goal to help you answer these questions by discussing:
What a CGM is and does
Evidence for CGM use in those with and without diabetes
The 5 Reasons You Don’t Need a Continuous Glucose Monitor (CGM), and
A brief list of Practical Ways to Balance Blood Glucose (Without a CGM)
What is a CGM?
A CGM is a medical device that is used by people with Diabetes to track blood glucose trends, day and night. The information collected and reported by the CGM is then used by patients and their providers to make educated decisions regarding exercise, medication administration, insulin regimens, food choices, and more. Such a device can be a crucial component to the management of diabetes and support significant improvements in blood glucose control.
Evidence versus hype
If you scour the websites and social media posts that market CGMs for general population use, you’ll find claims like, “it will teach you about nutrition”, “it will help you lose weight”, and “learn more about your body and what foods affect it”. In general, there are plenty of reasons why many people are jumping on the bandwagon.
Interestingly (though not surprisingly), despite the lack of evidence for these claims and the use of CGMs in the general population many healthcare providers and CGM manufacturing companies are urging the use of CGMs, saying the use of them is important to prevent pre-diabetes, diabetes, and other chronic conditions.
We’ve all been there - It can be really easy to buy into something when the person selling it mentions “the science” and what it shows, regardless if they actually share that evidence with you. So, what does the science show for the use of CGMs?
People with diabetes
Anecdotally, clinically, and through research, it seems consistently using a CGM often leads to improvements in quality of life, hemoglobin A1c, and glycemic control, such as increased Time in Range (TIR) and preventing and managing hypoglycemia (low blood glucose). In those with diabetes, A1c is said to have its limitations as it relates to the control and management of diabetes and blood glucose. This is because A1c is a marker of blood glucose balance over a 2-3 month period, and while its utility is unrefuted, data showing acute changes in blood glucose can be useful for better insulin and medication management. Thus the use of a CGM can be a beneficial addition to the treatment regimen.
While we have plenty of data that supports the use of CGMs in people with diabetes, research is still underway and it is acknowledged that unbiased studies are needed, as many (though not all) studies are funded by CGM companies and others are co-authored with board members of CGM companies.
General population
In contrast, evidence is sparse for the use of CGMs for promoting positive health outcomes in general population users. In fact, many of the studies done using this population were conducted to gather blood glucose data to better inform glycemic management and target recommendations for people with diabetes. From these particular studies it is impossible to infer there are benefits of using CGMs in the general population when these outcomes were never measured. At the same time, it is too soon to put any weight on anecdotal and clinical evidence for any measurement of long-term benefits.
The few studies that were not conducted for the benefit of those with diabetes measured potential benefits of using a CGM in non-diabetic populations. Outcomes such as increased motivation to change, increased physical activity, possible detection of early blood glucose regulation issues, and “weight loss” were measured. Some of the limitations of these studies are: short duration, small sample size, and differing interpretations and uses of “dysglycemia”, or poor regulation of blood glucose. It also appears that many of these studies fail to compare CGM data to the subjects’ A1c, and for the studies that did, it seems CGM data and the respective A1c values decently align to provide similar clinical conclusions - that someone either does or does not have pre-diabetes or diabetes. This is an important consideration because it begs the question: “does the general population need CGMs to detect early blood glucose regulation issues, or can we simply be more on top of tracking A1c and A1c trends?”.
Currently, a larger study is underway, measuring whether CGM use in a “generally healthy”, “non-diabetic” group of subjects will result in “optimization [of] general wellness and body weight and composition” over the course of 3 months to 5 years. It is worth mentioning this study is being produced and funded by a CGM manufacturing and health platform company. In fact, we often run into the same bias-related issues noted in the previous section. While bias does not render a study meaningless, a healthy amount of skepticism must be used and maintained, especially in light of a limited number of studies to support the use of CGMs in the general and non-diabetic populations.
Understandably, the data a CGM can provide is enticing to those without diabetes. Someone may want to improve performance, want to understand how diet and exercise affect blood glucose, or may have concerns about their blood glucose and would like to prevent the onset of diabetes. Regardless of the reason, people now believe this data can provide them with the knowledge to do these things.
While I cannot speak for each individual, it seems (at least for now), the promotion and use of CGMs in the general population creates more harm than good, and may not actually result in some of these outcomes or claims made. Let’s explore why this is the case.
5 Reasons You Don’t Need a Continuous Glucose Monitor (CGM)
1. Misuse and misinterpretation of data
Here’s a simple breakdown of common arguments and thought patterns:
Wears CGM → eats food → watches blood glucose rise higher than what “ought to be normal” → freaks out about it rising → determines the food eaten is not good for them
Wears CGM → eats food → watches blood glucose rise a little → still unsure but figures this is good because it didn’t rise as much → determines the food eaten is good for them
What the CGM doesn’t tell you is your blood glucose is going to rise and fall throughout the day (this is supposed to happen), and the variability is going to change because you don’t eat the same food or the same amount of it in the same environment with the same emotions and in the same physical state each time you eat it. We don’t live in an experimental bubble -l these things change often.
Blood glucose rising more and faster from eating a donut than from drinking a protein shake does not mean the donut is bad for you and will always lead to a spike in blood glucose when eaten. This comes down to the type of macronutrients that are in these foods and what is eaten (or not eaten) alongside them.
While protein can cause a rise in blood glucose, what is typically the culprit of a rise in blood glucose are carbohydrates (sugars). One of the ways to avoid frequent “peaks and valleys” (rapid rising and falling of blood glucose) is to pair carbohydrates with a fat and/or protein - your CGM doesn’t tell you this either.
2. Creates or exacerbates fear of carbohydrate-rich foods
As a result of these misinterpretations, we typically get avoidance and fear of carbohydrate-rich foods. This is apparent in influencer and provider videos all over social media and the endless comments on these posts, and during sessions with many of my clients.
I frequently hear (or read) comments that sound something like this: “I thought oatmeal was healthy, but when I ate it for breakfast my blood sugar was really high, so I stopped eating oatmeal”, “I heard that grapes spike your blood sugar, so I stopped including them in my diet”, or “I ate a banana and then my blood sugar went up 40 points to 124 after an hour!”.
Though there are plenty of examples, let’s break down the issues with the ones above: A blood glucose reading of 124 after an hour - okay, still within normal range, and if their blood glucose happened to rise outside of normal range after 2 hours does that mean the banana is bad for them? These foods are nutrient-dense, containing fiber, antioxidants, various vitamins and minerals (some of which are “shortfall” nutrients that we don’t usually get enough of, like Magnesium). If you are interested in health, do you want to cut out foods like that? Not to mention, carbs are crucial for performance, health, and, let’s be honest, happiness” (I mean, c’mon - a life without carbs? Sad face).
3. Supports (further) misconceptions about insulin
Poor, poor insulin. Insulin has been in the limelight for some time now as the culprit for all your metabolic problems. Insulin is a vital hormone, and it is meant to increase and decrease throughout the day as we transition back-and-forth between the “fed state” and the “fasting state”, the period immediately following a meal and the time in between meals, respectively. Keep in mind, while we know a lot about insulin, we don’t know everything there is to know about insulin. Couple this with circulating disinformation and misinformation and you got a seriously misunderstood hormone.
Insulin is an “anabolic” (building) hormone that is influenced by many physiological and metabolic processes. It plays many important roles and influences the health and function of nearly every cell and organ in our body. It is most known for storing glucose and fat, and aiding protein synthesis (i.e. building protein) - all-in-all, very good and helpful things.
When we eat, insulin is released by beta cells in our pancreas to shuttle the glucose in our bloodstream to various organs such as the liver, muscles and fat tissue. The glucose and fat that are stored are used for multiple purposes in the body, such as body temperature regulation, hormone regulation, energy, muscle contraction, and more. Oftentimes, the larger rises in blood glucose shown by a CGM are translated into “an issue” because this means insulin is rising to meet the glucose demand. People either think (or are told) this means their pancreas is working too hard, are likely insulin resistant, are at risk of developing metabolic syndrome or diabetes, and/or are going to gain a significant amount of weight.
However, insulin rising does not automatically mean any of these things. Yes - ideally the pancreas isn’t pumping out a lot of insulin to meet abnormally high levels of glucose in the bloodstream on a frequent basis (key phrase here is “frequent basis”). Yes - insulin promotes storage of fat. BUT, you can support prevention of metabolic abnormalities by engaging in the health behaviors in the next section, and you aren’t “packing on the pounds” each time your insulin rises.
4. Tends to lead to rigid, diet-like food rules and beliefs
And what does having rigid, diet-like food rules and beliefs often do? Creates a stressful and overall poor relationship with food and body.
In all seriousness, this is what the misconceptions around, and misuse of CGMs often trickle down to. Let’s think about it: if you have fear of a food - any food - what thoughts, emotions, and behaviors does that typically cause? Sure, you can face fear and “get through it”, but often there are negative bodily sensations and mental and emotional difficulties in some capacity while you “face your fears” - is that how we should feel around food or while eating food? (I hope your answer was no!).
This is why truly understanding the data a CGM provides is crucial. What is equally important is having an understanding of how food and the body interact, and how the body metabolizes food. For example, rather than cutting out a food or food group, you can simply manipulate the types and amounts of macronutrients in a meal or snack to balance your blood glucose and prevent large peaks and valleys. Moral of the story, you can (and should) still have oatmeal, bananas and grapes!
Speaking of “diet-like”, another consideration is how long people without diabetes will sustain their new lifestyle and motivations derived from using a CGM. How long will people be able to avoid the “unhealthy” foods that spiked their blood glucose? How long will people keep up with the constant influx of CGM data and manipulation of this data? If you know someone with Type 1 Diabetes, you likely hear this is no small feat, and financially speaking, unless you are “rollin’ in the dough”, an important consideration is the continuous cost of CGM sensors. This is certainly a consideration many people with diabetes know and struggle with.
5. You don’t have a diagnosis of diabetes
You might be thinking, “but what if I have diabetes and just don’t know it?”. Fair question - it is true that many people diagnosed with Type 2 Diabetes likely had diabetes far before their actual diagnosis and awareness of the disease. That is precisely why it is important to practice the health behaviors in the next section! Though before we do that, I hope you’ll consider a few more things.
Many people with diabetes struggle to afford and don’t have access to CGMs due to reasons such as poor healthcare coverage, no healthcare coverage, and the cost of CGMs and CGM supplies. Meanwhile hundreds of people without diabetes are shelling out money for CGMs of their own. Talk about a slap in the face to people with diabetes. In fact, Carolyn Todd, a freelance writer and former SELF health editor, provided a brief but insightful article about how the diabetes community has been reacting to this and how CGM use in the general population affects those with diabetes.
Practical Ways to Balance Blood Glucose (Without a CGM) and support chronic disease prevention
Stay up-to-date on your yearly labs. Be sure to include hemoglobin A1c, a helpful marker that provides information about your blood glucose balance and risk of developing pre-diabetes and diabetes.
Eat balanced meals and snacks and pair your carbs with a buddy. A balanced meal is one that includes sufficient protein, carbohydrates, fat, fiber and color. Pairing carbs with a buddy like fat or protein helps to balance blood glucose.
Eat consistently throughout the day and do not skip meals. Starting with breakfast, aim to eat a balanced meal or snack every 3-4 hours.
Consistently move your body in ways you enjoy and reduce sedentary time. In other words, aim to move your body more!
Eat before and after exercise
Manage stress and take care of your mental health
For a more detailed overview of ways to balance your blood glucose, take a peek at part 2 of this article, Practical Ways to Balance Blood Glucose (Without a Continuous Glucose Monitor).
You don’t need a CGM, you need labs and a Dietitian
Your blood glucose, health, and wellbeing are far more nuanced than what is typically shown in marketing videos and social media posts. A CGM will not tell you what you need to know about nutrition and how to balance your blood glucose, but a Dietitian can.
Likewise, if improved performance is your goal, a dietitian specializing in sports can help you do this without unnecessary spending on a CGM.
All that to say, if you choose to use a CGM anyways, make sure it is a quality device and you are consulting with a dietitian who has an in-depth knowledge about the details and nuances of how to balance blood glucose.
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