Continuous glucose monitoring (CGM) in healthy people: why is it useful?

When we hear about devices that measure blood sugar levels, we usually think of diabetics. However, more and more completely healthy people have started using continuous glucose monitoring (CGM) systems to understand how their body reacts to food, physical activity, sleep, and stress. This has become part of a new health-conscious and biohacking culture.

Preventive medicine doctor Sergey Saadi explains how CGM works and why continuous glucose monitoring in healthy individuals can also be beneficial for those without diabetes.

How does CGM work?

A CGM is a small sensor attached to the skin that measures glucose levels in the interstitial fluid 24/7. Measurements are taken every 1–5 minutes, and the results are sent directly to a smartphone.
For diabetics, this is vital to prevent hypoglycemia and complications. For healthy people, however, CGM becomes a personal biohacking tool — showing how the body reacts to different foods, coffee, exercise, poor sleep, or stress.

Blood sugar levels affect everything — energy, focus, mood, appetite, and even the speed of aging.

What do studies show?

A 2022 study published in Scientific Reports found that 15.4% of healthy participants experienced high blood sugar episodes after meals — glucose levels exceeded 7.8 mmol/L (ideally it should be below 6.5 mmol/L). For 2.6% of participants, glucose rose above 11.1 mmol/L, which meets the diagnostic criteria for diabetes. All of this occurred in people without a diabetes diagnosis.

This suggests that even people who feel healthy can experience blood sugar fluctuations, especially after eating high-glycemic-load foods. Insulin resistance — where cells become less sensitive to insulin, often due to consistently high carbohydrate intake — leads to higher blood sugar, and prediabetes as a precursor to type 2 diabetes can develop long before symptoms appear.

What can you learn with CGM?

• How specific foods affect a specific person’s blood sugar (e.g., a banana may cause a big spike in one person but not in another).
• How the order of meals matters — eating protein and fiber before carbohydrates softens the blood sugar response.
• What happens at night — whether glucose rises due to a late dinner or alcohol.
• How the body responds to physical activity — for some, glucose rises after exercise, for others it falls.
• How the body tolerates stress, including work-related stress.

Health benefits for a healthy person

CGM can bring significant benefits even to those without metabolic disorders. It helps to better understand which food choices or lifestyle factors cause sharp blood sugar fluctuations, which in turn helps prevent overeating and excessive sugar consumption.

Many of my patients have noticed that their sugar cravings decrease and their focus and energy remain more stable throughout the day when they make conscious choices. CGM also makes it possible to see how sleep quality and meal timing affect blood sugar, helping to create a rhythm that supports better rest. Most importantly, CGM allows for the prevention of insulin resistance and metabolic disorders at an early stage, when lifestyle can effectively intervene.

For this reason, CGM is becoming increasingly popular among biohackers and anti-aging enthusiasts. Glucose control is, for them, a way to keep cells younger for longer, reduce inflammation, and slow aging by consciously managing metabolism.

For example, there is much talk now about glycation — irreversible damage to body structures caused by elevated glucose, which is one of the drivers of accelerated aging. CGM helps bring attention to this and prevent excessive glycation.

What’s the catch?

CGM is not a toy or a miracle cure. Without understanding physiology, one might become anxious about every glucose spike. Short-term rises after meals or workouts are normal. It’s important to monitor trends, not isolated values.

Using CGM does not replace a healthy lifestyle, but it helps to shape it more precisely.