Do you need a glucose monitor? Wellness enthusiasts are using diabetes arm patches to take control of their blood sugar

• Continuous glucose monitors (CGMs) have become a hot wellness trend for people without diabetes.
• Proponents say CMGs can help people make more personalized and proactive decisions about their health.

Elite cyclist Tracey Jacobs knew something wasn't right when easy training rides started to feel like all-out efforts.

Jacobs, 57, has national championship wins and more than two decades of training under her belt. But what should have been simple intervals started to leave her feeling bogged down and overwhelmed with fatigue.

"It was frustrating," she told Business Insider.

The problem, it turns out, was her pre-workout habit of carb-loading with sugary foods, partly from anxiety, and partly because she assumed that as a lean endurance athlete, she needed a quick source of energy to power her intense efforts.

Eating too much sugar too quickly was backfiring, and Jacobs felt overloaded at first and then crashed later. She compared it to putting too much fuel in a car. "I was flooding my body with all this food and carbs within an hour, with no time to digest and hydrate," she said.

Jacobs started monitoring changes to her blood sugar with the help of a device called a continuous glucose monitor — an increasingly trendy wearable.

Continuous glucose monitors, or CGMs for short, were FDA-approved in 1999 for people with diabetes to keep constant tabs on their blood sugar levels. A sensor, inserted just under the skin via a tiny needle, measures the glucose (sugar) in the fluid around the cells, and provides ongoing updates on.

Until recently, you needed a prescription to get one. The FDA approved them over-the-counter in March. Companies can now market CGMs to anyone, no prescription necessary — be it the 100 million Americans with prediabetes, or any of the other 200 million adults who want to harness their health.

Naturally, as more people seek personalized solutions to optimize their bodies, the market for CGMs has skyrocketed. It is projected to more than double from an estimated value of $6.8 billion in 2023 to $20.2 billion in 2032, according to Global Market Insights.

Jacobs said a CGM, recommended by a fellow athlete, was a game changer. She was able to track how her body was responding to food, and use that data to perfect her training and performance. It was like tracking her heart rate or knowing her VO2 max: It gave her a clearer insight into the inner workings of her body, and a sense of control.

Working with a sports dietitian, Jacobs started tapping into more complex carbs, eating more, and eating earlier so she could have lasting energy. Her fatigue vanished. "After three hours of riding, I had a ton of energy, power in my muscles, and I didn't feel spikes of being up and crashing, I was just able to last longer, later," Jacobs said.

Why does blood sugar matter?

Your blood sugar level measures how much glucose is in your blood, which comes from breaking down carbohydrates you eat for energy.

Balancing blood sugar is crucial for people with diabetes, who can face life-threatening consequences if their levels drop too low or spike too high.

But wellness companies like Levels and Nutrisense increasingly argue that blood sugar is an important metric even if you don't have diabetes, since it ties into holistic lifestyle factors ranging from diet to sleep to exercise.

Through various health tech products, these companies aim to offer consumers more insight into how their daily habits affect their blood sugar, and help them analyze patterns to land on what behaviors can help them feel and perform their best.

"Understanding your glucose patterns is like having an MRI on how all the sort of holistic features of your daily choices are working together to generate metabolic health," Dr. Casey Means, co-founder of Levels, a health tech company with an app that syncs with CGMs, told Business Insider.

Controlling blood sugar may also help people address chronic health issues to manage or prevent long-term illness.

Gayle Pagano, a 56-year-old Florida resident, told Business Insider she started using a CGM through Nutrisense after struggling with weight gain and joint pain. She was edging towards prediabetes, and doctors wrote it off as a natural side effect of aging.

"I basically had to get sick to have coverage for getting sick," Pagano told Business Insider.

After reading about how age-related hormone changes can affect blood sugar, she started tracking hers, and noticed a pattern. Eating refined carbs like bread spiked her blood sugar, and she felt worse. Even ostensibly healthy foods like salads seemed to be a problem if they were store-bought.

"It's been shocking. The things you would think are OK to eat, they're just not," she said.

With the help of a nutritionist, she started making changes. Growing up in an Italian home, Pagano was reluctant to give up pasta, but found she could still enjoy some carbs with simple habits like making the noodles herself and eating protein first.

Since then, she's lost 50 pounds, and saw dramatic improvements to her fasting glucose, fasting insulin, and A1c (a measure of average blood sugar levels).

Can you really prevent diseases by monitoring your blood sugar?

Pagano isn't alone in struggling to get medical care in the gray area between borderline health metrics and an active diagnosis.

In the typical healthcare paradigm, you may have to wait months or even years for regular checkups to detect a problem. Companies are positioning CGMs as a way to cut out the waiting game — what if you could proactively control your health before developing an illness?

"By giving people access to their own health data, they can understand with a lot more clarity exactly where they stand and whether the choices they're making are having the impact that they want rather than having to wait six months or a year down the road for just a scrap of information given them to them by their doctor," Means said.

She said it it isn't a matter of telling people to ditch carbs or start intermittent fasting. It's about giving people tools to understand what works for them.

CGMs are great giving you a peek at your body's inner workings in real time, accurately reflecting your blood sugar levels at a given moment, and showing how those levels change in response to certain habits.

The problem is that science isn't very good at telling us exactly what those numbers mean yet. While CGMs can help people with diabetes avoid dangerous extremes, it's not clear what happens between those upper and lower extremes.

That doesn't mean Pagano or Jacobs are wrong about the benefits — it just means we're operating in a scientific gray area.

"There's no evidence. But just because there's no evidence doesn't mean it's not correct," Dr. David Klonoff, an endocrinologist and medical director of a diabetes research institute in San Mateo, CA, told Business Insider.

For Klonoff, there's a risk that people investing in a CGM may get little in return, or could simple experience a kind of placebo effect, since paying more attention to your habits drives healthier behaviors.

Clean eating can be unhealthy

Some experts are concerned that letting blood sugar dictate our diet too much could prompt extreme and unhealthy eating behaviors. Constant food monitoring can contribute to orthorexia, a detrimental fixation on so-called "clean" eating.

Social influencers with no apparent medical expertise point to blood sugar spikes to warn against eating healthy foods like fruit or rice, saying they cause brain fog, weight gain, and various catastrophic health issues.

"Disordered eating or having a poorer relationship with food is a significant issue, and I think it's plausible that using a CGM or tracking could potentially lead certain people who are susceptible toward that," Dr. Jonathan Little, a professor at the University of British Columbia who specializes in metabolism, told Business Insider.

Research doesn't support the fear that rising blood sugar after a meal is cause for concern in otherwise healthy people.

"What makes me perturbed is when people use statements like 'those are prediabetes glucose levels', or 'I ate this and my glucose went to diabetes levels,'" Klonoff said, "We don't have the evidence to know that's a bad thing."

So, should you wear a CGM?

Little predicts that CGMs will soon be another standard metric collected by everyday electronics along with data like our step count, heart rate, or sleep scores.

People want more information about the inner workings of their bodies, and health wearables can also be a status symbol to tout your health-conscious cred.

Not everyone is happy about this looming trend. People with diabetes have raised concerns that people who need the devices can't afford them, and rising popularity of the tech could make access even harder. However, widespread use could also drive innovations, like over-the-counter options, that may make CGMs cheaper for everyone, as some market reporting suggests.

Little and other metabolism experts are not convinced that wearables can give us more actionable data than we already know.

Do you need an arm patch to make the point that nutrient-dense carbs like whole grains and fruit are healthy, or that chowing down on ultra-processed food may make you feel worse over time?

"I don't think for the typical exercising person or person trying to optimize health, knowing blood sugar levels at every time of day is super helpful," Little said.