Continuous Glucose Monitoring

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“We start to, you know, numbers start to be overlaid onto everything like we’ve got some kind of headset on and we’re looking through it and there’s little value numbers attached to our foods and to the actions we take in our lives, and that’s tremendously unhealthy, I think, and can descend – you know, people I’ve interviewed and I’m sure people that you work with – can descend into pathology, right, where you’re constantly afraid that that equation is not right and you need to keep upping it and the output needs to be better and that you’re falling short. That’s not a good place to be.”

Dr. Alan Levinovitz, PhD, to Christy Harrison, MPH, RD, CEDS, in Food Psych #94

Earlier this month, a friend asked me about an email he received from a company trying to sell him a subscription to their continuous glucose monitoring (CGM) service. Since some of you are likely unfamiliar with it, CGM technology allows its user to automatically track their blood sugar levels around the clock. The monitor itself is a small sensor typically placed on someone’s abdomen or arm, and it contains a needle that measures sugar concentration in the skin’s intercellular fluid. A transmitter attached to the sensor sends the information to a separate device, such as a smartphone, on which the user can view their blood sugar data. As the American Diabetes Association discusses, CGM is a legitimate medical tool that diabetics can utilize to help manage their condition.

What was surprising about the email that my friend received is that the solicitor was not marketing their CGM service to diabetics, but rather to the general population. Their subscription service provides users with CGM devices, tools for tracking their food consumption, and access to a team of dietitians who analyze the data and help clients to examine the link between their eating and blood sugar levels. That may sound innocent enough, but I have concerns.

Their website (to which I am purposely not linking in order to avoid driving traffic their way) features enticing language like “Reinforce Good Habits,” “Promote Longevity,” “Manage Weight,” and “Gain Energy.” With approximately 51% of adults wanting to lose weight and some estimates claiming that 45% of the general population experiences fatigue, these calls to action seem designed for mass appeal. Their pitch continues, “While each journey is unique, we’ve found that remarkable improvement to your health and well-being can be achieved in just a single year,” and includes alluring testimonials, such as, “I was really in a place where I thought I kind of knew my body and I know what I’m feeling. I WAS WRONG.”

When I clicked on the “Get Started” link, the following page presented me with a multiple-choice question regarding my goals. This is the first of approximately a dozen questions, each on its own page, that opened up for me to answer. Between questions, a quote from one of their staff dietitians affirmed – based on my answer to the preceding question – that I was in the right place and they could help me. Using the back button, I changed my answers a bunch of times to see if I could produce a different result, one in which they would say their service is not appropriate for me, but that never happened. My impression is that they welcome everyone as a customer, which must make for a great business model.

Dangers exist in overemphasizing a single parameter of health and insinuating that everyone can benefit from focusing on it. While people may debate the quantity and identities of the various aspects of health, all of the models that I have seen agree that health is multifaceted. Depending on the particular model in question, categories may include emotional health, social health, and physical health, among others. Taking a closer look at physical health yields subcategories, such as anthropometric, biochemical, and clinical measures, and each of these has numerous parameters within them. Casting a bright light on one variable, such as blood sugar, while leaving the others in the twilight is an oversimplification of health, and to suggest that everyone – not just those with a known issue with their glycemic control – would benefit from doing so is at best misleading.

An overarching danger is that someone could pursue better blood sugar levels at the expense of other aspects of their health. For example, a user could adopt eating behaviors that may keep their blood sugar in check, but create or exacerbate issues with their cholesterol or blood pressure. Perhaps someone else begins to view foods that spike their blood sugar as “bad” and others as “good,” thereby bringing about or worsening disordered eating. Others may pursue better blood sugar at virtually any cost, eliminating or severely restricting certain foods, socially isolating themselves so they can eat exactly as they think they should, all the while feeling that what they are doing is not good enough and they need to be more diligent, thereby taking their disorder up a notch with each iteration.

Thinking about this CGM service reminds me of the debate surrounding full-body CT scans that some suggest could enable doctors to catch budding diseases in their infancy. Check out this 2017 Food and Drug Administration article, particularly the following quote, and note the parallel between the problem with these scans and what this CGM company is doing.

“CT is recognized as an invaluable medical tool for the diagnosis of disease, trauma, or abnormality in patients with signs or symptoms of disease. It’s also used for planning, guiding, and monitoring therapy. What’s new is that CT is being marketed as a preventive or proactive health care measure to healthy individuals who have no symptoms of disease. Taking preventive action, finding unsuspected disease, uncovering problems while they are treatable, these all sound great, almost too good to be true! In fact, at this time the Food and Drug Administration (FDA) knows of no scientific evidence demonstrating that whole-body scanning of individuals without symptoms provides more benefit than harm to people being screened.”

Similarly, while CGM can certainly be a helpful tool for some people with known blood sugar stability issues, whether the potential benefits outweigh the potential risks of applying the technology to someone without such a diagnosis is murky. In essence, this pros-vs.-cons question is what Dr. Levinovitz seemed to be getting at in his quote that kicked off this blog. It’s not that applying quantitative measures to our bodies and behaviors is always a negative; it’s that doing so is not always a positive either. Oftentimes, whether signing up for a CGM subscription service, buying a Fitbit, or downloading a calorie-tracking app, people go into such endeavors based solely on sales pitches and what they hope to get out of the experience while unaware of the risks that come along for the ride.