What is a Continuous Glucose Monitor – and Why Everyone’s Talking About Them?
- April
- Sep 19
- 6 min read
You may have heard the term CGM – Continuous Glucose Monitor – especially in discussions about diabetes. But increasingly, people who don’t have diabetes are exploring these tools. The appeal is obvious: rather than a snapshot, you get a moving picture of how your blood sugar is behaving throughout the day and night, in response to what you eat, when you move, how you sleep, how stressed you are. And that picture can teach you a lot about your body’s hidden responses — sometimes revealing imbalances before they turn into problems
How Do CGMs Work?
A CGM is a small sensor that’s inserted just under the skin (commonly upper arm or abdomen). It doesn’t draw blood constantly, but it measures glucose in the interstitial fluid — that is, the fluid around the cells — which tracks quite closely with blood sugar, though it can lag a little behind.
The sensor is attached (with adhesive) and connected to a transmitter. The transmitter sends readings to a smartphone app. You see your glucose every few minutes or so (depending on the device).
Many devices show trends: how fast glucose is rising or falling, how high and low it goes, what spikes happen after meals, what dips in glucose overnight or during sleep.
What It’s Like to Wear One?
It’s usually quite straightforward to put on. The sensor is small, and adhesive patches are designed to stay put even with light activity. Some people do get irritation or problems with adhesive, but generally most find them fairly comfortable.
Changing depends on the device: many CGMs need replacing every 7–14 days; some longer-lasting ones last 10-14 days, or even more. (There are also implantable versions lasting months, but those are more specialised, usually for people already managing diabetes.)
What Kind of Information You Can Gather
Type of Insight | Examples |
Post-meal glucose spikes | Which meals send your blood sugar high and fast. You may think a food is “healthy,” yet see a big spike. |
Glucose dips | When blood sugar falls (perhaps overnight or after a high spike) you may feel fatigued, shaky, or “hangry.” Knowing when these happen helps you manage steadier energy. |
Variation in response | Same food on different days might give different responses depending on sleep, stress, prior food, exercise and what you are eating it with. |
Effect of fibre, fat, protein | How adding fibre/fat/protein to a meal can blunt spikes; what combinations work for you. |
Effect of lifestyle factors | Sleep quality, stress, and exercise all influence blood glucose levels. Seeing in real time how poor sleep or a stressful day can change your glucose curves is powerful feedback. |
How CGMs Can Help Improve Health & Wellness
Here’s where things get especially interesting. Blood sugar balance isn’t just about diabetes. When glucose levels spike and fall greatly and often, this can cause metabolic stress.
Some of the consequences:
Inflammation: Repeated sharp glucose spikes are associated with increased oxidative stress, inflammatory markers, endothelial stress. Over time this can contribute to a low-grade systemic inflammation state, which underlies many chronic illness risks (cardiovascular disease, metabolic syndrome, etc.).
Better energy regulation: Stable glucose = more stable energy and mood; fewer cravings. When your blood sugar crashes, you may feel shaky, tired, or start craving sugar/carbs. CGMs can help you spot patterns and adjust.
Weight management and metabolic health: Although evidence is still emerging, people who see their glucose fluctuations often become more motivated to adopt dietary or lifestyle changes. This can help in reducing insulin resistance, improving fat metabolism and reducing portion sizes or between meal snacking.
Preventative potential: For those at risk of pre-diabetes or with family history, or borderline lab values, CGMs can uncover early signs of dysregulation that regular check-ups or HbA1c may miss. This is especially useful for those that have higher red blood cell turnover (like women with a heavy menstrual cycle) who may have a falsely lower HbA1c.
What the Research Tells Us: Not All Foods Are Equal
One of the biggest take-aways from emerging research is that we all respond differently to foods. What spikes one person’s blood sugar may hardly blink another’s. Which means “healthy diet” can be very personal.
Some examples:
A recent study comparing responses to potatoes vs. rice vs. grapes found that potatoes caused the highest glucose spikes in people who were insulin resistant or had poorer beta-cell function. But others did much better with the same foods.
Sweet potatoes tend to have a more favourable profile (slower rise, more fibre) compared to white (regular) potatoes — though cooking method, ripeness, and other factors matter — but some people have a hyper glucose response to sweet potato.
The effect of pairing carbohydrates with good fat, with protein, or with fibre (for example eating some vegetables and protein (legumes or animal sources) with the carbs; or adding nuts/olive oil etc.) shows consistent blunting of spikes in many studies.
Using a Nutritional Therapist: How the Data is Most Valuable
If you use a CGM by yourself, you'll likely learn a lot. But working with a nutritional therapist amplifies the benefit:
They can help you interpret your glucose curves in context — what’s expected vs what is signalling concern.
They can help you design meals, choose portion sizes, and combinations of foods to manage glucose in ways tailored to your physiology.
They can help you explore not just the food that spikes you, but the why — is it fibre? Is it lack of sleep the night before? Is it the timing of the meal? Is stress or hormones involved?
They can also help align the CGM data with other biomarkers (inflammation, lipids, HbA1c, perhaps more bespoke ones you might be monitoring) to get a more holistic picture.
Caveats & Things to Consider
Because CGMs are powerful, they also require responsible use:
For people without diabetes, there’s still limited evidence that CGMs lead to long-term hard outcomes (like reduced disease incidence) though early studies are promising. This is where it is all down to the user -- How will you use the information that you gather?
Data overload: seeing every little fluctuation can become overwhelming, or lead to anxiety/fixation on “perfect.” It’s important to use CGMs as tools, not as judgment.
Cost and access: depending on device, how often replaced, etc., these can be expensive. The ROI depends on how much you use the insights and for how long you use the device.
Interpretation: just because glucose rises doesn’t always mean “bad” — the context matters (what you ate, activity, sleep, etc.)
Practical Tips If Considering a CGM
Choose the right device: Think about wear time (7-14 days vs longer), how it connects to apps, calibration needs, comfort of wearing.
Keep food and lifestyle logs: If you note what you eat, when, how you slept, exercise, stress — you’ll get far more value from the data.
Experiment mindfully: Try making one change at a time: e.g. eat more fibre, change cooking method, adjust protein/fat, shift meal timing. See what effect it has.
Don’t aim for perfection: Look for patterns. Aim for more stable curves, fewer big spikes/crashes, rather than obsessing over every point.
Adjust gradually: As you notice which foods cause bigger responses, you can make shifts. For example, swap white potato for sweet potato (or a smaller portion), experiment with legumes, cut down on refined carbs, include protein/fat/fibre etc.
Bottom Line
Continuous Glucose Monitors are no longer just tools for people with diabetes. They’re becoming potent instruments in the wellness toolkit — helping people understand their bodies, reduce inflammation, stabilise energy, make better food choices, and potentially catch metabolic drift before it becomes disease.
If you decide to explore one, especially with the guidance of a nutritional therapist, the insight you gain can be transformational. It’s not about perfection — it’s about greater awareness and smarter small steps.
To Wellness!
April
For those that would like to learn more:
Individual variations in glycemic responses to carbohydrates and underlying metabolic physiology (Nature)
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