Is CGM the next revolution in wellness?

After spending three weeks with a pseudo-AI body attachment called a continuous glucose monitor (CGM), I believe every adult should have access to one. Here's what I learned.

Wearing a CGM is like having artificial intelligence plugged into your body. A small sensor sitting on your skin gives a surprisingly insightful and potentially life-changing piece of insight: how your glucose level changes as you go about your day, and night. As with conventional AI, the benefits you can gain from this are still evolving. But there's already plenty you can learn from using the technology now – as I did.

What’s CGM for?

As is implied by the name – it's all about glucose. Glucose circulating in our body and blood comes from the stuff we consume – and also our body’s response to life in general (like exercise and stress). We need insulin to be able to absorb the glucose in our blood.

Continuous glucose monitoring was originally designed for people with diabetes – a condition where, broadly speaking, the body doesn’t make enough insulin (type 1 diabetes), or isn’t sufficiently sensitive to insulin (type 2). This means people with type 1 and some people with type 2 diabetes need to add insulin into their body to help keep their glucose levels stable.

Too much or too little glucose is bad (in its extreme it can cause death, but most generally, over time, it can lead to severe problems like heart disease, stroke, foot amputation, blindness and other longer term health complications). So it’s vital that people with diabetes who are adding insulin can check their glucose levels and make sure they don’t go too low or too high.

Prior to CGM, people with diabetes needed to draw blood from their finger throughout the day to check their glucose levels, and/or rely on judgement as to what their body was doing. CGM now gives virtually painless and round-the-clock access to glucose levels, which – depending on the make and model of CGM – can be displayed on a smartphone app, a dedicated receiver, and/or a lifestyle device like a smartwatch, Fitbit or Garmin watch/computer.

Key take-aways

• CGM is a small, wearable sensor

• It measures glucose levels, 24/7

• Users see in real time the unique way their body responds to food/drink/movement/stress etc

• Such direct, tangible feedback could help all adults with weight management and general wellbeing

What does CGM feel like?

A miniscule needle about 5 mm long goes into the skin, attached to a transmitter about size of a 10p coin that sits on top. I expected it to feel like a sharp scratch (like a vaccination or blood draw), but in reality I felt nothing except the pressure of the applicator on the skin with the sound of a slightly anxiety-inducing ‘twang’ as it went in.

When in place, I hardly noticed the sensor at all, except for the odd clumsy bump on a door frame as I walked through. (Both me and my sensor thankfully survived these bumps. To help avoid them altogether the guidance is to wear the sensor on the back of your upper arm – some sensors can also be worn on the abdomen and, in younger people, the upper buttocks).

Here's what happened when I applied my first CGM sensor

CGM technology has been evolving over the past two decades, amassing a vast body of clinical evidence. In just the past few years health authorities across the globe have recognised the impressive health and quality of life benefits of using CGM, and the technology has become more widely available and even funded by state health services and insurance companies for people with diabetes who meet certain criteria.

With programmes like Zoe (which incorporates CGM use), and newer generations of CGM coming out all the time, the technology is being made more accessible to the wider population. So this includes people who don't have diabetes and are looking to improve their general wellness, like me.

* DISCLAIMER * I have worked for one of the companies making CGM more accessible – during which time I was offered a free CGM sensor to try out. I loved it so much that I bought my own sensor to use a second time – plus some extras as gifts for loved ones – and I aim to continue this self-investment every few months for the foreseeable future. The thoughts I share here about CGM are my own.

So what have I learned as a non-diabetic using CGM?

1.      My body lies to me

I feel hungry almost all the time. And almost all the time my body (in terms of its glucose level) is absolutely fine. In the first 10.5 days of using the sensor, I veered towards a low glucose level only once, despite trying out intermittent fasting.

To me, this is a life-changing insight. Call me naive, but I used to think hunger was a sign of low blood sugar. I was hungry – so I ate. I now know this isn’t the case. In fact, most of the time I think my body would prefer me not to eat.

When using CGM – and for a few weeks afterwards – I stop snacking about 90% of the time. Yes, I still feel hungry, but somehow knowing my glucose levels are stable makes me able to psychologically manage this hunger so much better than I have ever been able to before. I don’t consider myself as dieting, I’m just ‘managing my glucose.’ I guess this is similar to psychological weight loss programs like Noom. (Though unlike the claims made by Noom I haven't yet managed to make the assumed healthy impacts of not snacking to persist long beyond I stop using the sensor).

For my second time using CGM I really wanted to test my theory that my body would sort itself out in using my reserves to keep my glucose levels stable if I decided to stop eating. So I stopped eating. I wouldn't have got away with this if my husband was around (he's pretty good at perverting my natural tendency towards lunacy) so I did it when he was away for a few days. Which also meant I was looking after the kids solo for a few days (in case you needed evidence of my lunacy).

Needless to say, after a 36 hour fast and a continuous "Critical Low" glucose level alert in the middle of the night (which you can't turn off, well, unless you turn your phone off but I didn't think of that at the time, did I) I gave up on the fast and ate a packet of raisins. Although the kids were sad they missed out on the raisins they were probably happy I didn't crash the car the next day. Oh well – turns out I can't get away without eating for too too long. But I think 36 hours of stable glucose with no food intake is still pretty impressive. It's amazing what our bodies can do.

2.      Keeping a stable glucose level helps me feel and sleep better

Life (especially with kids) gets in the way of healthy habits. I have a goal of only eating past 9pm and having pizza only once a week. That goal often blurs to several times a week (if not every day).

Of course I knew the drill – don’t eat large, carb-heavy meals in the evening – so I could have guessed those evening pizzas weren’t ideal. But until I used CGM, I didn’t fully appreciate the direct impact of this on my life.

I've now seen first hand the curves that show how a late, heavy meal sends my glucose levels on a roller coaster for the next six hours plus. And, overnight, this was having a sizeable impact on my sleep quality.

Here are those glucose curves

Impact of large meals on body glucose levels

Solution A: eat earlier, eat healthier. And for an added bonus, go for a walk after too (see point 3).

Impact of earlier healthier meals on overnight glucose levels

Solution B: have half a pizza, ideally earlier. My glucose levels calm down so much more quickly, and I still sleep ok. Plus, the remaining half pizza means lunch is sorted the next day. Double pepperoni win.

Impact of eating half a pizza on overnight glucose levels

3. Exercise is a magic bullet...with a catch

If I want to stop the glucose spikes I don’t have to avoid the ‘bad foods’ – just mind the way I eat them. I already learned that eating earlier in the day is better for me. But how can exercise impact this further?

Say I want a double scoop ice cream cone with all the toppings (Amorino, how I love you). This would usually send my glucose levels on an all alarm-bell-ringing excursion. But when I ate such a totally necessary fuel while walking reasonably briskly – my glucose barely blipped.

This works for me, at least in the short-term. Note of caution: it might not stop fat depositing in dangerous places (which I am warned of by my dad, a fairly lean rowing and clotted cream enthusiast, who had a heart attack at 60 and was told he had the heart of a 90 year old) – though fat isn't all bad and I think our knowledge of how this actually happens is evolving (thanks Tim Spector). Either way, walking hopefully isn't going to hurt.

On the flip side...when I exercise strenuously – even if not for very long, say a 15 min HiiT session – I frequently get a surge in glucose that takes me over the supposed happy limit. To some extent this annoys me. I know that extremely high glucose levels are probably bad as they cause extra free radicals to be released into the body that can all kinds of problems. So I want to avoid these extremes. But does that mean I need to avoid certain types of exercise? The first time I used CGM, I thought so. It meant I swapped short, sharp exercise bursts for longer, moderate walks. But the second time I used CGM, I wanted to investigate further. Turns out I can get back to those endorphin-boosting and easy-to-fit-in HiiT workouts, but I just need to be mindful of my ideal workout window (maybe about 2 hours after food, not really any longer. I will investigate this further next time).

4. Alcohol skews the system

Yeah, yeah, alcohol is bad. Call me naive again, but until I used CGM I had no idea how much it was impacting me really.

The first day using my first CGM sensor, I had a G&T – and within 15 minutes my CGM gave me an "Urgent Low Soon" alert. This alert means your glucose levels are dropping at such a rate that you need to take action (i.e. eat some sugar) to prevent hospitalisation. Remember, CGM is primarily for people with diabetes using insulin – where insulin can send glucose levels dangerously low. So for me to have this kind of alert from just a G&T surprised me somewhat, and made me look into what might be happening.

I think most people know it’s best to avoid drinking alcohol on an empty stomach. Although a brief search of the medical literature showed me that, although people's reactions to alcohol vary widely, an ‘empty stomach’ can actually mean not eating for 3–4 days (while drinking after an overnight fast can be ok!). My body’s response (a dramatic drop in glucose levels) might be uncommon, and for some might be a sign of liver problems, but in reality was probably due to the combination of exercise and fairly low food intake I had had earlier that day. Note to self: do not G&T alone (a bowl of nuts is necessary company).

I guess that part isn't particularly revolutionary. What was life-changing was seeing the direct impact of alcohol on my glucose levels overnight afterwards – and how that felt like a direct correlation with my sleep quality. This led me to discover the actual joy of non-alcoholic gin and wine varieties and – bar the odd 'full-fat' glass here and there (just to check) – this impact on my life is here to stay. Thanks CGM.

Summary of things I've learned from CGM

• Most of my hunger isn't real

• Stable glucose links directly to my wellbeing

• Exercise is helpful, but timing is key

• Alcohol isn't worth it for me

So why do I think every adult should get one?

According to the UK government, 64.0% of adults aged 18 years and over in England were estimated to be overweight or living with obesity in 2022–23. This has been an upward trend for since the survey began in 2015. Why is this, and why aren't the various Public Health England 'do more exercise' (e.g. couch to 5k) and 'eat better' (change 4 life) campaigns doing enough to reverse the trend?

There are many speculations – the cost of living, quality of diet, shoddy evidence for current 'health trends', and cultural factors such as the erosion of the value placed in mealtimes, to name a few. As with any nationwide health issue, the answer is (un)helpfully – it's complicated. And when things are complicated, we have a tendency to put them off till another day (which is one of the reasons I'm writing this several months after I intended to!). And that's why I think CGM could play an important role in mainstream health.

CGM clarifies health choices

By translating our choices (i.e. the things we consume and our physical activity) directly into the real-time impacts they have on the body, CGM gives much-needed and unavoidable feedback on a deeply personal level. When wearing a CGM, healthy decisions are no longer 'something I'll think about later' or 'diet starts tomorrow'. The impact on your psyche can start as soon as you insert the sensor. The results can cut through some of the complication and grey space that usually enables us to feel more comfortable about the less 'healthy' decisions we make.

That being said, CGM isn't going be a fix-all solution. Would every adult be willing to try it and learn from it? As with other examples of AI – of course not. But as it becomes more and more mainstream I think it will stop being the specialist diabetes health technology it has been – and could become an important part of the puzzle of interventions many of us need to nudge us towards better health long-term.

About me

I have a couple of autoimmune conditions but in general I would consider myself in decent health (a recent test said I have below normal blood fats, whoop whoop!).

As a copywriter I do a fair amount of sitting at my desk, but as a mum I’m up and about a lot, and I exercise regularly, aim to eat well (even if I rarely meet those goals), and maintain a fairly healthy weight.

It’s important to note that every body is different and the way our glucose levels fluctuate in response to life is unique. I’ve highlighted the most general things I’ve learned, but please be cautious when considering if anything applies to you.

I also need to be cautious when extrapolating from my very small scale, unblinded studies on myself! Hence the need I feel to do it all again every few months or so...and next time I might try CGM along with Aria, or another AI-augmented health coach – to help extract even more from all the insights it offers.

And how about you – are you tempted to try CGM?