After authorities approved two new devices for use without a prescription, millions of Americans may soon be carrying blood-sugar monitoring monitors in their arms. Is there a method to make us healthier? Is the data just another source of diversion?

Last June, Cindy Bekkedam was startled awake in the middle of the night by an unexpected alarm. It came from her phone and it was loud, like an emergency alert. More precisely, it was coming from a recently downloaded app that was connected to an implanted glucose sensor in her arm.

This app claims that while she was sleeping, her blood sugar fell to a dangerously low level, setting off the alarm.

"I ate a granola bar after getting up in the middle of the night," she remarked.

Millions of diabetics have been using continuous glucose monitors (CGMs) for years; these devices measure blood sugar levels in real time. Ms. Bekkedam, a dietitian in Ontario, Canada, installed hers so that her diabetic patients may benefit more from technology.

However, her two-week experiment ended up serving as a kind of warning.

She said, "I was freaking out." "I really wondered, like, really, do I have diabetes?"

She didn't. She also discovered that her blood sugar levels were completely normal after doing some additional investigation. But without a medical condition requiring it, receiving continuous updates on her highs and lows in blood sugar caused some unwarranted anxiety.

She stated, "I think that's where people could go down a rabbit hole."

But because of two new Food and Drug Administration (FDA) permits for more general use, these gadgets might soon be in the hands or on the arms of a lot more individuals. Abbott Laboratories declared this week that two over-the-counter CGMs, one for those without diabetes, had been approved by the federal government.

The number of people using CGMs is already on the rise, and major American cities' morning commutes are a great place to observe the distinctive arm patches.However, experts claim that even in the absence of evidence of harm, there isn't much to support paying the high monthly fees—up to $300 (£240) if you're not a diabetic.

Abbott is marketing its Lingo continuous glucose monitor to individuals “who want to better understand and improve their health and wellness.” It is a CGM for non-diabetics. It is already available in the UK and was one of the two devices approved for sale by the FDA. Medical device safety and efficacy are assessed by the FDA under the 510(k) regulatory procedure; marketing claims are not considered in this process.

An Abbott representative told the BBC that "managing your metabolism so you can live healthier and better" requires an understanding of your body's glucose levels.

Abbott cited research demonstrating the effects of glucose spikes on general health and the function of CGMs in monitoring them in support of his claim that flattening glucose curves may help with energy, mood, and sleep.

Though the medical community is skeptical of such claims, doctors do concur that CGMs have improved the care of certain individuals with diabetes dramatically.

Type 1 diabetes is when an individual's pancreas stops producing insulin, so regular injections are needed. Type 2 diabetes is more common and occurs when the cells in the body become resistant to insulin and so more is needed to keep blood glucose levels within a normal range. It can usually be controlled through medication, diet, exercise and close monitoring, although some take insulin. Traditionally, diabetics monitored their blood sugar with finger-prick tests, but CGMs can alert people with diabetes when their blood sugars are running dangerously high and low, and if insulin needs to be injected.

But many experts say that the evidence for CGMs improving the health of non-diabetics is effectively non-existent. They insist the devices are, at best, a distraction and at worse could lead to dangerous fixations.
A growing trend

CGMs are big business. Market leaders have estimated sales will reach $20bn globally over the next four years.

Earlier this year, the FDA cleared the sale of an over-the-counter CGM made by Dexcom, meant for Type 2 diabetics who don’t use insulin but want to avoid regular finger-prick tests. And some new CGM startups, like Signos, Nutrisense and Levels Health, now market prescription devices off-label as tools for energy, mood and metabolism.

The devices are becoming popular among some in health, wellness and sports industries.

Dutch marathoner Abdi Nageeye, who will compete in the Paris Olympics, told Reuters earlier this week he is wearing a CGM to try to better track his body's available energy.

Others, including some in the scientific community, have also expressed interest in the effects of glucose on metabolic health.

Nick Norwitz, 28, who graduated from Oxford University with a PhD in nutrition and is currently in his fourth year of medical school at Harvard, said he believes CGMs can be powerful tools because glucose is “a bellwether for what’s happening hormonally in your body”.

He has studied their use while at Harvard, and said he welcomes more research in the field.

Mr Norwitz said he believed that over the long term, the hormonal changes associated with frequent glucose spikes could cause negative effects, including through fat gain.

But, he added, glucose is just one metric, and shouldn’t drive all health decisions.

“To be clear, I don't think that means if you eat a mango and have your blood sugar go up that it’s 'worse' for you than were you to have a plate of bacon,” he said.

Interest in how CGMs can help you change your diet has flourished in some corners of the internet too. Depending on your algorithm, a search for glucose monitors on TikTok or Instagram could lead you to dozens of testimonials from health and wellness influencers espousing the technology’s benefits.

One such influencer, Brittney Bouchard, who promoted a particular CGM start-up on her TikTok and offered her followers a discount code, said wearing a CGM helped her adjust her diet to reduce glucose spikes. She received an affiliate commission when people bought the device through her link.

“I could tell a difference immediately, in my energy, my sleep and my brain fog,” said Ms Bouchard, a 41-year-old health coach from Los Angeles.

In her opinion the CGM showed her that her body “was unfortunately very, very sensitive to carbohydrates… even fruit”, she said, recalling that eating a pineapple had made her feel “jittery” and sick.

“If I have oatmeal I will be tired within an hour.”
A solution in search of a problem

But while some researchers and businesses claim that CGMs can have great benefits for the average person, many in the scientific community are sceptical, pointing to a lack of evidence.

Spikes in glucose are a symptom - not a cause - of diabetes, said Oxford researcher and dietitian Dr Nicola Guess. She said there is “no benefit” to CGMs for those who are not diabetic.

“Normally you would identify a problem and invent a solution to fix it,” she told the BBC. “This is backwards. It’s like we’ve got this technology, now we just have to find groups of people who we can convince that they need this technology.”

One key issue experts point to is that it is surprisingly hard to find much data on what blood sugar patterns look like in people without diabetes. This makes it hard to interpret an individual's results in a meaningful way.

And most people’s sugars will spike with fruit - a food group rich with vitamins and nutrients - but that's not a reason to stop eating it.

Dr Ethan Weiss, a clinical cardiologist with the University of California, San Francisco, agreed there is scant evidence that tracking glucose levels in people without diabetes can measurably improve their health.

“I’m aware of studies that show you can change your diet and you can decrease glucose spikes. I’m not aware of any studies showing that [tracking glucose] is actually doing anything beneficial, in a meaningful way, like reducing your risk of disease,” he said. “I think mostly it’s the devotees who believe it.”

But, Dr Weiss added, he was not aware of any studies showing the CGMs caused damage, either.

Others, including Dr Guess, said that the potential for harm was very real. Instead of focusing on the foundational building blocks of health - things like regular exercise, and a nutrient-rich diet - trackers like CGMs encourage us to focus on the minutiae of imperfect metrics. And, in worst-case scenarios, they can foster new problems, like disordered eating.

“I worry that instead of doing simple things to improve our health we are turning mealtimes into scientific experiments,” she said.

“I just feel like in some ways people have forgotten the point of living.”