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Image by Michael Dziedzic


Continuous Glucose Monitor (CGM)

What is it?

A continuous glucose monitor is a wearable biosensor that can give you real-time information about your blood sugar (glucose) level. This information is vital to people with Type 1 or Type 2 diabetes, for whom high or low blood sugar can be life-threatening. However CGMs are also valuable for people without metabolic impairment, serving as a window into how diet and lifestyle decisions affect their health. Consistently high glucose levels or frequent glucose spikes and crashes can lead to health effects like fatigue, brain fog, and depression and are associated with several chronic diseases, including cancercognitive decline, stroke, diabetes, and cardiovascular disease. CGM can help you maintain stable glucose levels before metabolic dysfunction like insulin resistance (prediabetes) sets in and sets the stage for more severe disease.

Here’s a deeper look at this biosensing technology. 

Why Use a CGM?

The benefit of a continuous glucose monitor is that it provides a more granular, real-time look at your blood sugar than alternative methods such as using a glucometer, which reads glucose from a drop of blood, or glucose tests at your doctor, such as fasting plasma glucose or HbA1c. These other methods provide only a single measurement, a snapshot in time. 

This can fail to show you how much your blood sugar is spiking and crashing (known as glycemic variability. They also fail to reveal trends over time or reactions to particular foods. Even if you tested your blood with a glucometer after a meal, you can’t see the entire rise and fall pattern, so your reading may be misleading. A continuous glucose monitor is like listening to the whole symphony instead of just individual notes.

Who Should Use a CGM?

People with Type 1 diabetes can’t make insulin to help maintain stable blood sugar, so they need to monitor their glucose levels closely to keep blood sugar from getting dangerously high or low. Without a CGM, the only way to do that is to use a finger-stick glucometer dozens of times a day. 

But CGMs can also provide several valuable insights that can benefit people with or without diabetes:

  • Glycemic variability: This describes the “spikiness” of your glucose curve. Ideally, we want glucose to remain stable and rise only slightly after meals. If you have high glycemic variability, your blood sugar is frequently spiking and crashing. Not only can this impact your mood and energy, but it can also have long-term impacts as well. Studies show that these big spikes and dips in glucose can damage tissues more than elevated but stable glucose levels. Extreme glucose variability has been linked to heart disease, diabetes, and metabolic dysfunction. High levels of variability can also indicate that you’re becoming insulin resistant—your body is unable to use insulin efficiently to control glucose.     

  • Reaction to individual foods: Our blood-sugar reactions to foods are highly individual. While your blood sugar may spike from a cookie but not from a banana, someone else may have the opposite reaction. Our glucose reactions are also affected by our microbiome, genes, overall fitness, sleep statusstress, and what else we’ve eaten recently. Because of all these factors, simply reading carb content on a label or going by glycemic index is not sufficient to help us find the diet and lifestyle that will allow us to maintain stable glucose. 

  • Train our bodies to be metabolically flexible: Our body has two primary sources of fuel: glucose and fat. Burning fat produces ketones, which have many health benefits. If our body is burning glucose, it’s not burning fat (in fact, insulin, which is produced when our blood sugar is high, blocks fat burning). Metabolic flexibility refers to how efficiently your body can switch between these fuel sources. Without that flexibility, people may struggle with weight loss, fatigue, or excessive hunger because they cannot efficiently tap into and metabolize their fat stores for energy since their bodies are conditioned to rely on glucose. By using a CGM to help eat for stable blood sugar, we train our body to switch to fat seamlessly when it can.

  • Catch metabolic dysfunction early: We can begin to develop insulin resistance more than 10 years before it shows up in our fasting blood sugar test at the doctor. A CGM can help us see our total postprandial blood sugar response, giving us more insight into how our body handles a glucose load. And the earlier we catch metabolic impairment, the easier it is to arrest its development before it reaches prediabetes or diabetes. 


Continuous glucose monitoring can improve the quality of life for any individual, whether they have diabetes or not. Access to consistent and accurate data about our blood sugar can help us make informed and healthy diet and lifestyle choices to help support our longevity and wellbeing.

- The Levels team

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