Do You Need to Use A CGM (Continuous Glucose Monitor)?

March 21, 2024
Photo by Jasmin Schreiber

With the popularity of wearable tech, ads for CGMS (such as Nutrisense) are likely popping up in your Facebook and Instagram ads.

But you’re not overtly diabetic or maybe not even pre-diabetic so… do you really even need one?

Your primary doc has likely said no and your insurance company may have said no as well if you do not meet the criteria of “medical need” for these devices but like so many things, there’s much to be gained in the “gray” area vs. the overt black and white: you have diabetes or you don’t.

Recently I was asked if these devices are “bogus” by a listener of the Dr. Brooke Show. They are certainly not bogus and can be very helpful for women in figuring out what works for them. As I always say, not every one needs every thing! This article will help you understand if a CGM is right for you.

What is A Continuous Glucose Monitor or CGM?

A continuous glucose monitor is a small sensor that samples your interstitial fluid (this is the fluid between cells in your skin which reflects your blood glucose level) with a very short wire filament.

This wearable sensor that you change every couple of weeks allows you to see how your food choices, stress, sleep and exercise impact your blood sugar. As with Nutrisense, they are often paired with an app where you can track your food, exercise, etc. so you can really see how these daily choices impact your blood sugar and how that relates how you feel each day as well as how it all correlates to your overall health, bloodwork, other testing, etc.

Extreme highs and low are dangerous for our health and blood sugars that run high too often can certainly lead to more serious health issues such as diabetes, cardiovascular disease and even Alzhemer’s.

But more than a root cause of more significant diseases, blood sugar balance is a vital part of your overall health impacting everything from:

  • Neurotransmitter balance and other aspects of brain health which impact mood, memory, etc.
  • Hormone balance (i.e. cortisol, thyroid, estrogen and progesterone)
  • Metabolism (difficulty with fat loss and building lean muscle)
  • Inflammation and oxidative stress (which will impact energy, stamina, brain fog and all hormones)
  • And even seemingly unrelated issues like joint health


I often say on the Dr. Brooke Show that I’ve been talking about blood sugar for twenty years and it’s sooooo boring! It’s not the sexy, shiny new thing like keto or carnivore or whatever (though keto and carnivore will for sure impact blood sugar!) and it’s not specific to a thyroid problem or perimenopause – it’s vital for all hormones.

It’s vital, it’s basic, but boring or not it is something you must know about and figure out what works for you to keep it in check. This not only decreases risks of chronic illness but it helps you feel better every day and favorably impacts all your hormones. It is really that important!


Who Should Use A CGM?

CGMs are often thought of by the medical community as only a tool for overt diabetic patients, but we know insulin resistance happens on a continuum with control getting worse as diet impacts over time take hold in our physiology (i.e overshooting our carb tolerance, overeating or too frequent eating, inadequate protein, etc.), as stress and lack of sleep wear on us over years and as our hormones change with things like perimenopause (as estrogen wanes, insulin resistance and carb tolerance will worsen).

And it’s not just higher blood sugars and insulin resistance that is the problem, many of us feel badly when our blood sugar is erratic – varying from higher to lower numbers, even if those numbers are considered “normal” values.

This bouncing around all day leaves us tired and fatigued; fighting sugar, carb and caffeine cravings; feeling cranky and moody and possibly battling headaches. With erratic blood sugar we lack the energy to work effectively, to get through our workouts and enjoy time with our families and friends.

Since insulin resistance and blood sugar problems develop over time and it’s swinging from high to low that may impact us as much as overly running very high or very low, why not intervene before things get as far as diagnosable diabetes?

Work With Dr. Brooke

It’s My Mission to Help You!



How A Continuous Glucose Monitor CGM Can Help You Regulate Blood Sugar

Blood sugar is one of those things you can’t “see” so it can feel very intangible. I mean most women have no idea if their blood sugar is 150 or 80.

You may know if it’s super low cuz you feel hangry, irritable, shaky or light headed and feel better when you eat something. Or you may know that you feel sleepy or irritable or get a raging headache if you have a cookie on an empty stomach because it shot up quite high. But most people do not know what their blood sugar is doing and unless they’ve been told by their doc that it’s dangerously high on a blood test.

Thus the argument that only those with very high numbers consistently need to monitor their blood sugar is kinda silly because without monitoring it, most of us have no idea what our blood sugar is doing!

I teach a biofeedback system called ACES in my book Hangry that helps women tune in to cues about their blood sugar (specifically about the hormones insulin and cortisol). ACES stands for appetite, cravings, energy and sleep (learn more about that here).

Learning how to tune into these hormone cues coupled with data from a CGM, you can really glean a lot about your blood sugar as a cause of a variety of symptoms and it can give you powerful insights into your current results (i.e. inflammation that won’t go away, difficulty losing weight, poor sleep, fatigue, etc.).


It’s About More Than Just High Blood Sugar

What we also miss when we are only focused on high blood sugar and overt insulin resistance is that variability in our blood sugar is not only hard on our hormones and physiology but a lot of swinging from lower numbers to higher is also a problem

For example, if your glucose never goes above 120 or below 70 with spot checks on a glucometer or periodic readings on a blood test you may think you have no issues with your blood sugar. However, when using a CGM you may see that you go from 70-120 frequently and this variability or jumps of 50 points is an issue when we want your blood sugar in much tighter control for optimal health. Variability should be closer to 15-20 points and using a CGM is really the best way to see this.

Tighter glucose control is important for our health but also without it we can suffer with a host of common symptoms.


Typical Symptoms of abnormal Blood Sugar

What most women may not realize is that unstable blood sugar can feel like:

  • Headaches
  • Mood changes: irritable, anxious or depressed
  • Poor exercise stamina and recovery
  • Sleep issues (especially waking in the night and having a hard time going back to sleep)
  • Worse PMS
  • More gas/bloating
  • Issues losing body fat
  • Issue gaining muscle mass
  • Poor energy or unstable energy throughout the day
  • Cravings (especially for sugar and starchy carbs)
  • Brain fog and issue with memory
  • Difficulty regulating your appetite and food intake

When you use a CGM, even for a short time you can really make meaningful changes in your day to day habits, your nutrition and your lifestyle that will help you feel so much better – and lower risk of chronic disease to boot.


It’s Not Just About Carbs

This was a real eye opener for me personally and the answer to my spike in glucose was not to lower my carbs, it was to manage my stress differently.

Lastly, when we think of higher blood sugars we usually think of cutting sugar, lowering carbs or maybe trying something like keto. This may be part of the issue for sure but what is incredibly enlightening when using a CGM is that you may not have eaten a thing but got mad at your husband and see a spike of 20 points.

Many will also notice how much worse their control is or how much more of an exaggerated response they have the day after a poor night’s sleep.

In this regard, CGMS can be so helpful for you to know which habits: i.e. sugar or sleep or stress management, are the biggest issues for you to address.


Continuous Glucose Monitors Help You Step Away From Diet Dogma

Food is often touted as good or bad but the truth is you may have a more nuanced or unique response to certain foods than most people.

For example, cottage cheese and yogurt are typically thought of as great protein sources but they make some women’s blood sugar spike a bit. Or how about oatmeal? Often recommended as a great breakfast but can cause a huge rise in blood sugar for most women despite being called a “good carb”.

And other foods that are thought of as bad for blood sugar like bananas or potatoes might not cause you the rise in glucose that you’d expect. Or maybe that spike is easily remedied by including some protein or healthy fat with these foods or you take a quick walk after eating them. This can allow you to utilize these foods for other reasons (convenience, preference, etc.) or simply keep you on a less restrictive list of foods that work for you – and that is a big win if you ask me.

As well, it’s super interesting to see that an almond milk latte is basically a non even but an oat milk latte is a 35 point spike for you when you may have thought either of these non dairy milk substitutes are similar.

A CGM can help you create a nutrition plan that truly works for you based on your unique responses to foods instead of following pop nutrition rhetoric that a food is good or bad (i.e. carbs) or this nutrition strategy is a must for every women (i.e. fasting or keto).


If You’ve Ever Felt That What Used to Work Doesn’t Anymore

As women pass into through their 30s and into their 40s and beyond a common refrain is “what used to work for me doesn’t anymore. They are often frustrated by poor sleep, weight gain and crappy energy and using a CGM can be a powerful tool to figure out what does indeed work better for you.

Age related hormone changes can be baffling for women and they may struggle to figure out what moves as female hormones are a moving target through the years, this is one of many things that can be helpful as well as all things I work with women on individually in my practice.

Work With Dr. Brooke

It’s My Mission to Help You!



But…CGMS Aren’t Perfect

One of the biggest critiques of a wearable CGM is its accuracy. First it’s always recommended that you calibrate your CGM with a more traditional glucose monitor for a couple of reasons.

The main reason is that the CGM is measuring interstitial fluid (which is fluid between your cells vs. your actual blood) and this can be off by several points. It is good to know that if your CGM reads 5 points lower than your glucometer that you account for that when you interpret your data.

But Dr. Brooke, if a CGM is off then why bother? You are looking for trends and for information more than you are looking for an absolutely accurate numbers and as long as you know that 100 means 105 in reality you have the ease of the CGM and the accuracy of the more traditional – and more painful and inconvenient – finger stick.

As well, the sensor is sensitive to pressure so if you push on it you will get a strange reading. If you sleep on your side for example, that pressure on the sensor can show a very low reading at night that isn’t accurate.  But you will still have all the other data from the day and the night and you can disregard the outlier.

I cover all of the troubleshooting for CGMs in this episode of the Dr. Brooke Show with Carlee Hayes from Nutrisense.


CGM’s Help You Do Better

In the end, save for a few drawbacks what I see these devices doing is driving positive change – which is what it’s all about. With blood sugar being something less tangible than say the scale, a device like a CGM can be not only insightful but you can use the info you glean to literally do better at your next meal.

What I see in practice is that it helps women do more of what works for them and waste less time stressing over things that don’t seem to be as impactful for them. That is a big check in the plus category if you ask me!

Do I think everyone needs to wear a CGM forever? Absolutely not, but even using it for a few months a couple times a year can be incredibly enlightening. And certainly if you are trying to figure out what works for you it can save you so much guesswork!

As well, if you’re utterly clueless about what your blood sugar is doing it’s also very worthwhile to see what’s going on internally. Lastly, if you are struggling because nothing seems to work for you then by all means get some data with a CGM.

The wonderful thing about apps like Nutrisesne is that they come with dietitian support so you can get some guidance in terms of what to change in your diet and lifestyle to get better results.

And of course if you need my help with any of this be sure to reach out to inquire about becoming a patient and feeling better!

Dr Brooke Kalanick, ND, MS, LAc

Dr Brooke Kalanick is a naturopathic and functional medicine physician specializing in thyroid issues, autoimmunity, histamine intolerance, and women's hormone issues including PCOS, perimenopause, endometriosis and infertility. She is the best selling co-author of HANGRY: Balance Your Hormones & Restore Your Joy in 5 Simple Steps. She is also the co-host of the Sarah & Dr Brooke Show podcast. To learn more about Dr Brooke click here.

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