If you haven't noticed, diet personalization is a huge market (and getting bigger by the day). There are at-home saliva, urine, and blood test strips enabling you to "eat according to your genetics”—whatever that means, frankly—or “monitor how your body reacts to everything you eat or do”.

Apparently, these enable you to optimize your lifestyle and nutrition choices for tip-top health and wellbeing (FYI: there’s zero evidence they work).

And if you thought:

• Spitting into vials of test tubes,
• Pricking your fingertips with a needle, or
• Peeing onto test strips

… at set intervals (think: every morning, for instance)—all in the name of better health—sounds mighty extreme, well, you better hold your horses because there's this:

Continuous glucose monitoring (CGM).

Doesn't ring a bell? No worries, because that's what we're about to cover in a sec.

How does continuous glucose monitoring work?

To understand continuous glucose monitoring, there are three things you need to know about continuous glucose monitors (CGMs):

1. They involve implanting a sensor under your skin (usually on your arm or abdomen), which continuously monitors glucose levels—hence, the term “continuous glucose monitoring”—in your interstitial fluid. That’s the fluid found between your cells.
2. Most continuous glucose monitors can transmit that data to your smartphone, allowing you to see real-time information about how your glucose levels are affected by your various lifestyle choices (i.e., diet, sleep, exercise, and stress levels).
3. Continuous glucose monitors were initially developed to help people with diabetes monitor their blood glucose levels—freeing them from the burden of pricking their fingers multiple times a day to check their blood sugar.

Why are people without diabetes using CGMs?

So, at this point, we’ve established two things:

This begs the question: why are people without diabetes jumping on the CGM bandwagon (evidenced by the growth of companies like Levels, Nutrisense, and January)?

Well, here’s their pitch in a sentence.

“Find the best foods for you by seeing how they impact your blood sugar levels.”

To further elaborate on that, many companies state that continuous glucose monitoring could help non-diabetics understand:

• The relationship between their favorite foods and their blood sugar levels (e.g., does eating a donut make your blood sugar levels spike and crash, leaving you tired, sluggish, and unproductive?)
• How engaging in regular exercise (e.g., going for a short post-meal walk) helps improve blood sugar control
• Their risk of developing type 2 diabetes and other forms of metabolic disease (note: research highlights an association between large blood sugar swings, heart disease, and chronic inflammation—which, in turn, is linked with chronic conditions like diabetes, cancer, and arthritis).

Sounds convincing, right? You get to catch what’s going on in your body and make lifestyle changes to improve your blood glucose levels (and, in turn, your health).

Well, there are a few issues with this.

Benefits of continuous glucose monitoring for non-diabetics IRL?

First, and most importantly, there’s this: there are no benefits to using continuous glucose monitoring if you don’t have diabetes.

No, really. Here are a few reasons why:

• Bereft of scientific fundamentals: There is no evidence justifying claims about continuous glucose monitoring’s ability to facilitate health or performance in individuals without diabetes.
• Your blood glucose levels are supposed to rise post-meal: Eat carbs, and your blood glucose levels rise. It’s pretty duh because your body breaks down those carbohydrates (e.g., pasta, bread, and rice) into simple sugars which enter your bloodstream. And that's where insulin comes in: it prompts your cells to absorb sugar from the blood, lowering your blood glucose levels to healthy levels.
• Penalizes all carb intake: Wish for a perfect score on a CGM? Try a low-carb diet, like the ketogenic diet. But think about it: how is that a “hyper-personalized nutrition plan”? You could achieve the same results by simply cutting out carbs from your diet. Plus, what about all the evidence highlighting the importance of adequate carb intake for high-intensity exercise performance and longevity?
• Increases the risk for orthorexia tendencies: CGM diets work based on elimination. In other words: you'll have to cut out certain foods (likely your "favorite foods and snacks") for better blood sugar control and health. That can pave the way toward an unhealthy relationship with food. And besides, the truth is that there are no truly off-limits foods. All foods can—and should—be enjoyed in moderation.

Psst: find out why “eating clean” can be bad for you here:

Clean Eating Can Be Bad For You

While there’s no strict definition of ‘clean-eating,’ it always promotes whole foods and demonizes processed options and added sugars. Now, at this point, you must be thinking: ‘Isn’t that healthy for you?’ Clean-eating – sounds benign enough, right? Well, no.

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TBH, you don’t need continuous glucose monitoring

What does this all mean for you? If you don't have diabetes, continuous glucose monitoring for a "personalized nutrition plan" is plain unnecessary.

Also: have you seen the cost associated with continuous glucose monitoring?

Still worried about your blood glucose levels? Here’s some advice:

• Go for a medical check-up: Visit a licensed medical professional who can run blood tests on you to determine your risk for pre-diabetes or diabetes and guide how you should manage your blood glucose levels. Don't rely on a CGM; it isn't a diagnosis tool.
• Lifestyle changes to improve insulin sensitivity: Instead of obsessing over your daily blood sugar fluctuations, you'd do better by increasing your physical activity level (resistance training is fantastic for blood sugar level management) and losing fat mass (obesity is linked with insulin resistance). In addition, you could further enhance your fat loss efforts by adjusting your daily fiber, protein, and calorie targets.

Check out our past articles on fat loss:

How to Eat and Workout for Healthy, Sustainable Fat Loss

Long-term sustainability is key to successful fat loss; here’s how you can make small lifestyle tweaks (diet and fitness) to make that happen.

GymStreak BlogGene

Strength Training to Lose Weight? Here’s What Matters

How much you sweat, your heart rate, and muscle soreness—do these matter if you’re strength training to lose weight? Find out in this article.

GymStreak BlogGene

How to Eat Less without Starving Yourself

Creating a calorie deficit isn’t about eating less food. It’s really more about making smarter nutritional choices. Find out why in this article.

GymStreak BlogGene

New to the fitness game?

“Increasing your physical activity”—but how?

Lucky you, because GymStreak’s got your back. This AI-powered personal trainer app personalizes your workout routine based on your fitness goals, training capacity, and equipment availability. All you need to do is show up and give your best.