Continuous glucose monitors: should people who don’t live with diabetes be wearing them? | Natasha May

People living with diabetes have applauded public figures such as Este Haim for speaking out about living with the condition and visibly wearing continuous glucose monitors (CGM) in public. But another more concerning trend has emerged that has seen celebrities, elite athletes and influencers who don’t live with diabetes sporting the wearable device, which offers near real-time measurements of an individual’s blood sugar.

A video Gwyneth Paltrow posted on Instagram in May starts with the actor turned wellness influencer stretching with a CGM conspicuously on her arm before she proceeds to make grain-free almond and coconut pancakes with a strawberry compote. Many in the comments questioned her use of a CGM, with some saying she risked stoking a “dangerous trend” given many diabetes sufferers struggle to get access to them.

Other influencers have directly promoted CGMs to people who don’t live with diabetes, claiming it can help people manage their metabolism, and thereby improve energy, mood and sleep. Dr Fiona Willer, the president of Dietitians Australia, worries about the proliferation of the devices and questions whether some people may have “fallen down a wellness rabbit hole”.

What is glucose?

Glucose, the sugar in our blood, is “there to help fuel all of our cells – our muscle cells, brain cells, all of them – and so we do need sugar in our blood. It’s a bit like the petrol in a car,” Willer says.

“Any form of carbohydrate that we eat, whether that’s lollies or wholegrain bread, is turned into glucose, which makes its way into our bloodstream.” The body can also recycle glucose from the stored energy of food we’ve already eaten, Willer says.

Those with diabetes need to monitor their glucose levels because their bodies have trouble making or using insulin – the hormone created by the pancreas that helps move glucose from our bloodstream into the body’s cells to make energy.

The blood glucose of people who don’t have regulation issues still fluctuates across the day, going up and down depending on what we eat, physical activity level, as well as things such as whether we’re ill or going through puberty, Willer says. “For people who don’t have diabetes, that fluctuation will occur within a tighter range, while for people who do have diabetes, their blood glucose levels stray outside of what we would call the reference range.”

What do CGMs do?

People with diabetes previously had to use a finger prick test to measure their blood glucose levels. The CGM is a relatively new device that uses a sensor to measure glucose via the fluid between cells every few minutes and then sends the reading to a receiver or smartphone app. For people with diabetes, the reading can then help them manage their glucose levels by influencing how they eat or using some glucose-modifying drugs such as insulin.

Clinical endocrinologist Prof Jenny Gunton says CGMs can “hugely improve the quality of life” for people living with type 1 diabetes, as well as pregnant women who have gestational diabetes and people with type 2 diabetes on insulin.

What about people who don’t have diabetes?

Gunton, who heads the Centre for Diabetes, Obesity and Endocrinology Research at the Westmead Institute for Medical Research, says outside of these groups, wearing a CGM can be useful to understand blood glucose levels after various foods and exercise, but warns that “like any device that gives lots of information, CGMs can sometimes increase anxiety and stress”.

They are also expensive. For people who aren’t eligible for a government subsidy, it can cost more than $100 for a sensor that lasts just 14 days.

Should people without diabetes use them?

A study led by the University of the Sunshine Coast in 2022 found CGMs provide little benefit for healthy athletes without diabetes. Separately, researchers who analysed the available evidence of the utility of CMGs among people not living with diabetes in 2024 said that due to the lack of evidence, “we urge for the commercial claims suggesting the utility of the device in [this population] to be labelled as misleading”.

Willer welcomes people trying to understand how their body works, but says any idea of a “magic number” for glucose levels for someone who doesn’t have insulin resistance or diabetes is “completely imaginary”. She also says it could lead people to becoming unnecessarily restrictive with their diet and trying to control their body in a way that is not necessarily healthy.

“It’s a bit like calorie counting, in that it’s one metric that can give people the impression that it kind of wraps everything up together, that it is an indicator for everything. But just like calorie counting, it is actually hugely reductionistic, and it means that we lose so much context about why we eat, when we eat, the sorts of things we eat, and how food functions in our social and cultural experiences as well.”

Willer recommends for people who are interested in living a healthier lifestyle and want an individual approach to speak to a health expert rather than buy a product online.

“Even if they have purchased a CGM, a dietitian or another health professional will help understand, to help them interpret what’s going on with their numbers against their actual behaviours.”

Natasha May is Guardian Australia’s health reporter

Antiviral is a fortnightly column that interrogates the evidence behind the health headlines and factchecks popular wellness claims