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Not long ago continuous glucose monitoring (CGM) was a tool for people with diabetes. In 2024 over-the-counter versions appeared in the US: Dexcom Stelo and Abbott Lingo are sold to people who want to track glucose without a diagnosis. A coin-sized sensor sticks to the arm and sends a value to an app every few minutes. The question is what a healthy person should do with that curve.
What the sensor actually measures
A CGM reads glucose in interstitial fluid, not blood, so readings lag lab values by minutes and can differ noticeably. It does not replace a blood test and cannot diagnose. What it shows is what a single fasting test cannot: how fast glucose rises after a meal, how long it stays up, and what happens overnight.
Why it is interesting
Responses to the same food vary widely. In the PREDICT study of about a thousand people, individual glucose responses to identical test meals differed markedly, even between twins (Berry et al., Nature Medicine, 2020). That helps explain why “universal” diets do not work for everyone, and it is the basis for commercial personalized-nutrition apps.
In practice a sensor can show:
- which of your regular meals cause sharp spikes in you specifically;
- the effect of meal order, a walk after lunch, poor sleep;
- unusual overnight spikes and dips worth discussing with a doctor.
Where usefulness ends
For healthy people there are no convincing trials showing that watching the glucose curve improves outcomes such as cardiovascular events, diabetes or lifespan. Short post-meal swings are normal: a peak is not a disease. The danger is that people start fearing normal things and restricting healthy food because of a red arrow.
Rely on solid markers: HbA1c, fasting glucose, waist circumference, blood pressure, lipids. CGM is an add-on that makes sense for a short period (two to four weeks) to learn your responses, not something to wear permanently.
What GLP-1 drugs change
GLP-1 receptor agonists (semaglutide, tirzepatide) have become the main tool for treating obesity and type 2 diabetes in recent years and have shown fewer cardiovascular events in large trials in specific groups. They change the very meaning of metabolic control: many patients reach normal numbers without strict diets. But these are drugs with side effects and indications, chosen by a doctor. Why muscle mass matters more alongside them is covered in our piece on strength training .
How to use the technology sensibly
- If you have risk factors (family history of diabetes, excess weight, prediabetes), get an HbA1c first and discuss the result with a doctor.
- Wear the sensor for a limited time with a concrete question, for example how you react to breakfast.
- Do not compare your numbers with screenshots from social media.
- Change one thing at a time and repeat the measurement.
