One piece of wearable technology that is gaining a lot of attention in the health and fitness community is the continuous glucose monitor (CGM). While traditionally intended for people with insulin-dependent diabetes, people without diabetes are beginning to use these devices to “hack” their blood sugar.
But if you don’t have diabetes, is using a CGM worth your time and money? The answer may surprise you.
What is continuous glucose monitoring?
CGM is a wearable device that continuously monitors glucose levels without the need for traditional fingerstick tests. Unlike the fingerprint method called blood glucose (blood sugar), CGM checks for glucose levels in the interstitial fluid (the fluid between the cells). A small sensor inserted under the skin measures glucose levels, and a wireless transmitter sends the results to your cell phone or wearable device. It’s so cool, isn’t it?
The sensor in the CGM checks your glucose levels every few minutes whether you’re resting, exercising, working, or sleeping. Other features you may see on a CGM include:
- An alarm that goes off when your glucose level is too low or too high
- A system for tracking food, exercise and medications
- The ability to download your data to a computer or smartphone to see your glucose trend
- In combination with insulin pumps, the pump automatically adjusts insulin levels to glucose levels
To make sure your CGM is calibrated correctly, it’s important to test the blood drop on a standard glucose meter. The reading should be the same on both devices.
What are the benefits of using continuous glucose monitoring if you live with diabetes?
For people with type 1 diabetes (or type 2 diabetes requiring insulin), the information collected through continuous blood glucose monitoring is an important part of their diabetes care plan.
Glucose monitoring gives you information about how much insulin your body needs and when it needs insulin. This allows for better blood glucose management and fewer “glycemic excursions” (ie, blood glucose levels outside of your personal target). Keeping a person’s blood glucose levels under control can help prevent diabetes complications in the short and long term and improve a person’s overall health and quality of life.
There may also be some benefit to using a CGM in people who have prediabetes or who are at increased risk for developing diabetes due to family history or other health conditions, says Lauren Kelly-Chew, MD and head of standards for clinical products. More than one in three Americans live with prediabetes, she says, and more than 80 percent of that population don’t know they have the disease. Kelly-Chew explains that insulin resistance can develop years before it develops into prediabetes and is influenced by a variety of lifestyle factors, including diet, exercise, sleep quality and stress levels.
Using a CGM can give you a complete picture of your metabolic health and insulin resistance. This is important because the earlier a person understands their metabolic health, the sooner they can make changes to prevent or reverse the damage before it rapidly progresses to type 2 diabetes.
What are the health benefits of continuous glucose monitoring in the absence of diabetes?
For people without prediabetes or diabetes, the benefit of using a CGM is less clear. A study of 153 diabetics showed that their blood sugar levels were normal or normal. 96 percent at the time. Is it worth measuring something if it’s only four percent of the target? Many people would argue that it is not.
Another much smaller study of 19 people found that those who wore the CGM reported being more motivated to exercise. While this is a positive result, wearing a different piece of fitness equipment can provide the same motivation.
Overall, there are no studies in peer-reviewed medical journals that demonstrate the benefit of using CGM in the absence of diabetes. It is also important to note that wearing a CGM is not a good practice. There are some pitfalls to consider before jumping on the CGM bandwagon.
For people with diabetes, CGMs are not a fun toy that they can choose not to use if they don’t feel like it. They are an extremely useful, disturbingly expensive medical device that is out of reach for many people with diabetes.
Problems of using continuous glucose monitoring in the absence of diabetes
Although it seems relatively harmless, wearing a CGM in the absence of diabetes can have some complications. As Melissa Mitri, MS, RD, Melissa Mitri Nutrition explains, wearing a CGM can cause a person to worry unnecessarily about their glucose numbers. This can be especially harmful for someone with a history of disordered eating, food restriction, or anxiety in general. Diet culture is pervasive in our society, and careful monitoring of our bodies and fitness metrics can certainly fit into that.
Indeed, a study of 647 first-year university students examined whether wearing technology-based weight self-monitoring devices was associated with eating disorder behavior. They found that students who wore fitness technology were more likely to report eating disorder behaviors such as fasting, skipping meals, and excessive exercise. While no studies have looked at the effects of CGMs on disordered eating behavior, they may encourage an unhealthy obsession with getting glucose levels within a very tight target.
Anya Rosen, MS, RD, LD, IFNCP, CPT and founder of the Birchwell Clinic, also notes that incorrect dietary advice can be given with CGMS. In particular, there may be an incentive to limit carbohydrates.
For most people (including those with diabetes) a high carb restriction is unnecessary, and in fact can be extremely healthy. Rosen notes that if a person chooses to use CGM, they should work with a registered dietitian to include carbohydrates in a way that matches their individual metabolism.
In addition to developing a sensitivity to glucose levels, there are practical considerations when using a CGM. As Colin Kiley, RD, a registered dietitian and certified diabetes care and education expert notes, the problem with wearing a CGM when you don’t have diabetes is getting too many low glucose alerts, especially at night.
Keely explains that the sensors will trigger an alarm at a glucose reading of 70 mg/dL or lower. This glucose level may be normal in a person who does not have diabetes and is not taking any medications that lower blood glucose levels. The sensor can also alert you if you put pressure on it while you are sleeping. These alarms can be loud and disturb a person’s sleep. (Ask any diabetic about insomnia due to their condition and they’ll have a lot to say about it.)
Achieving continuous glucose control is a problem
In addition to developing an obsession with getting a “perfect” glucose reading, there are potential ethical problems with using CGMs with non-diabetics.
Why is it an ethical issue? CGMs are a life-saving technology that many people with diabetes cannot afford. CGM devices are often expensive and not always covered by insurance. In addition, the sensors must be replaced every seven to ten days, which can add up quickly.
According to the American Diabetes Association, inequities in access to CGMs affect low-income, elderly, and/or people of color compared to other diabetes patients. We know that low socioeconomic status is associated with an increased risk of type 2 diabetes. In other words, people who need CGMS the most often can’t afford it.
The idea that we need to know the minutiae of our biological processes feeds into diet culture. When you dig into the (lack of) research, promoting CGM to healthy people seems like trying to sell people something they don’t need to worry about. It is fear-mongering at its best.
For people with type 1 and type 2 diabetes who depend on CGMs for their livelihoods, the “trend” of using CGMs without diabetes can feel like a big slap in the face. After all, for people with diabetes, CGMs aren’t a fun toy that they can choose not to use if they don’t feel like it. They are an extremely useful, disturbingly expensive medical device that many people with diabetes don’t have access to.
If you have a family history of diabetes or have been diagnosed with prediabetes, a CGM can be a valuable tool to help prevent diabetes. But for the average healthy person, there is little evidence to suggest that using CGM has any health benefits. CGMs are just the latest in health fads, and until we learn more about how they work in healthy people, they may not be worth your time or money.