Glucose monitoring is a must for someone with diabetes, but could it also benefit healthy people who don't struggle with high blood sugar? Companies marketing continuous glucose monitors for non-diabetics certainly would have you think so.

A continuous glucose monitor, or CGM, is a wearable device designed to help people with diabetes more conveniently track their blood sugar levels on an ongoing basis.

"There's a huge role for these devices in people with diabetes," says Dr. Archana Sadhu, an endocrinologist at Houston Methodist. "Continuous glucose monitors help patients understand how their blood sugars are fluctuating in real time, enabling them to change behaviors and variables. Patients feel more empowered about managing their condition, and it certainly helps improve outcomes when patients have access to this type of information and guidance on how to use it appropriately."

Companies marketing these devices to healthy people often point to a supposed role in the prevention of diabetes. It's certainly a laudable goal. Type 2 diabetes is rising at an alarming rate in the U.S., and diabetes prevention needs to be more top-of-mind for us all. But does it really take wearing a device?

Plus, tracking blood sugar levels often isn't the key selling point. Instead, CGMs for non-diabetics are advertised as a way to:

• Optimize metabolism
• Lose weight
• Understand how your body responds to sleep and stress
• Keep consistent energy levels

Is any of it really true?

Do healthy people benefit from continuous glucose monitoring?

Outside of diabetes management, Dr. Sadhu is pretty skeptical — if not outright concerned — about most non-diabetics using a CGM.

"The only exception is for people with prediabetes," says Dr. Sadhu. "These are people who don't yet meet the criteria for type 2 diabetes, but we know they're on that trajectory if changes aren't made."

Dr. Sadhu and other endocrinologists try to sound the alarm for such people, stressing the importance of diet and activity level to prevent prediabetes. But she notes that there's nothing more convincing than tangible evidence.

"We prescribe the device to these patients on a trial basis, and they really do start to understand, 'OK, I need to avoid these foods since they really spike my blood sugar,' and, 'Wow, my blood sugar really dropped when I went for that walk,'" explains Dr. Sadhu. "Seeing these fluctuations with their own eyes and in real time is a really powerful motivator for change."

But for people whose blood sugar levels aren't a concern? Dr. Sadhu says these sensors simply aren't designed for them.

3 reasons to think twice before using a continuous glucose monitor if you don't have diabetes

Diabetes prevention is important, no doubt. But using a CGM isn't a good tool for a healthy person trying to accomplish this.

"I think the main thing to understand is that these devices aren't designed for persons without diabetes," says Dr. Sadhu. "It's a reminder to always do your research, always investigate the claim."

Fortunately, Dr. Sadhu has done some of the work for us.

Here are her three biggest concerns involving the use of a CGM, without the guidance of an endocrinologist or other specialist, if you don't have type 2 diabetes or prediabetes:

1. These devices aren't tested in healthy people

There are only three FDA-approved continuous glucose monitors on the market, and they're only approved for people with diabetes.

"What this ultimately means is that the devices available are only tested in people with diabetes for blood sugar management only," says Dr. Sadhu.

In other words, we can't really know whether any of the claims associated with CGMs — from promises of weight loss to better control over metabolism — actually have any merit for non-diabetics. Nor are the devices meant for such people.

"In the design of these devices, the data collection and algorithms are tailored to people with diabetes and people taking diabetes medications," says Dr. Sadhu.

What's critical to understand is that someone with diabetes is more prone to blood sugar spikes than the average, healthy person. And spikes are also much more concerning for this person, too. In addition, if they're taking certain diabetes medications that lower high blood sugar, like insulin, glucose levels are carefully monitored in order to prevent them from going too far in the other direction — dropping too low.

One of the functions of CGMs is to warn a person with diabetes or on diabetes medications when concerning thresholds are reached, but these limits don't mean anything for a healthy person.

"It's completely normal for a healthy 20- or 30-year-old woman to have fasting blood sugars in the 60s," explains Dr. Sadhu. "But this isn't normal for someone who's managing diabetes with insulin, for instance. These systems are designed to alert diabetics that a low blood sugar is occurring or about to occur and prompt them to take action, but that same reading may not be actually concerning for a healthy person."

2. Proper guidance is lacking for healthy people trying to use these devices

Whenever a new sensor comes out, Dr. Sadhu tries it out herself, so she can know how it works to help educate her patients. During a recent trial run, she consistently got low blood sugar alerts for the first two days.

"It was constantly alerting me that my blood sugar was low," says Dr. Sadhu. "As an endocrinologist, I know my glucose levels are perfectly normal. I know I don't have low blood sugar symptoms. I know I don't need to do anything about this alert. But here's this device telling me to take action to bring my blood sugar back up."

For the layperson using a CGM to self-monitor their own blood sugar readings, the concern becomes how the data is interpreted.

"The FDA-approved sensors are by prescription only, so the companies marketing them to healthy people must have a healthcare professional available to prescribe one to you. But then what?" asks Dr. Sadhu.

On the flip side, when someone with diabetes is prescribed a CGM, there are guardrails and plenty of education on what the readings mean and what to do about them.

"A patient can come back to me and I can actually download all the information from the sensor and go over their report with them," explains Dr. Sadhu. "I can say, 'OK, what were you doing during this spike?' And maybe the answer is, 'Oh, yeah, that's when I ate at a Tex-Mex restaurant for dinner.' Well, now I can explain why that caused a blood sugar spike and remind them that their body can't handle that much rice, tortillas and chips and give them advice for next time."

This level of guidance on how to interpret the data and actually make use of it just isn't there for healthy people.

"Let's say you're healthy and you notice a blood sugar reading of 160," says Dr. Sadhu. "You panic, because that's a spike, right? Well, that might be a perfectly fine reading for you, so long as it comes back down. But this is information that the general public doesn't necessarily know what to do with."

3. These devices could lead to a healthy person taking unhealthy actions

"My biggest concern about people using these devices in unintended ways is the anxiety it can cause and, because of that anxiety, the inappropriate actions that may be taken," warns Dr. Sadhu.

Back to the example of the healthy 20-year-old who gets a "low" blood sugar alert — what's the next step? Eating a quick source of simple carbs, like a bag of chips, to bring your blood sugar back up?

Think again.

"That's a completely normal reading for a healthy person, but now they're panicking about something they don't need to panic about and, potentially even worse, taking an unnecessary action that's actually unhealthy," says Dr. Sadhu. "Or maybe the person sees a spike and panics. But, again, a blood sugar spike isn't usually an immediate concern for healthy people."

How to prevent diabetes: What you can do instead

Preventing diabetes is a goal every healthy person should have.

But rather than relying on one of these devices, Dr. Sadhu has some simple — not to mention totally free — diabetes prevention tips she recommends everyone follow:

• Eat whole, natural foods
• Be physically active every single day
• Avoid processed foods
• Limit added sugars

"It really is as simple as diet and exercise," says Dr. Sadhu.

She points out that our metabolism is still in its prehistoric days, but our eating habits and food supply are not. We're giving our bodies man-made, preserved food that it's just not sure what to do with.

"We've far surpassed our body's metabolic ability with the modern era of food," says Dr. Sadhu. "What did our ancestors eat? Natural fruits, vegetables, whole grains, nuts, seeds and some meat here and there. What do we eat? Food that's been stripped of nutrients as it's run through a machine or ones processed to the point that it can last on a shelf for years."

We've also become more sedentary.

"I can't tell you how important physical activity is," stresses Dr. Sadhu. "There's a great study that I use in my lectures of how insulin lowers blood sugar at the cellular level and how exercise does the same thing but through an entirely different mechanism."

The logical question: Do you want to have to take insulin to lower high blood sugar, or do you want exercise to lower it naturally and prevent diabetes in the first place?