Are Continuous Glucose Monitors (CGMs) Useful for People Without Diabetes?

Key Takeaways

• Continuous glucose monitors (CGMs) are valuable tools for individuals with type 1 or type 2 diabetes because they help prevent dangerous drops in blood sugar (hypoglycemia).
• CGMs allow diabetics to monitor glucose levels continuously without frequent finger-stick blood tests.
• In people without diabetes, CGMs may offer limited benefits and are often marketed as lifestyle or weight-loss tools.
• Research shows little meaningful weight loss in non-diabetics using CGMs.
• Even in diabetics, CGMs typically reduce HbA1c levels by only about 0.3%, which is the minimum considered clinically meaningful.
• Many metabolic problems are driven not by high glucose alone but by excess insulin (hyperinsulinemia) and insulin resistance.
• Insulin resistance is strongly linked to chronic diseases including obesity, diabetes, heart disease, liver disease, kidney disease, infertility, and Alzheimer’s disease.
• The Zone Diet, combined with omega-3 fatty acids and polyphenols, may help improve metabolic control by activating AMPK, the master regulator of metabolism.

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If you have diabetes (either type 1 or type 2), a continuous glucose monitor (CRM) can be exceptionally useful, especially to reduce hypoglycemia.  Hypoglycemia is low blood sugar.   Mild hypoglycemia leads to symptoms like shakiness and sweating.  More severe hypoglycemia leads to seizures and loss of consciousness. This is because the brain requires a constant supply of glucose to function optimally.  So, for individuals with diabetes, using a CRM avoids the need for continuous blood testing for blood glucose levels to prevent hypoglycemia.  

What Is a Continuous Glucose Monitor (CGM)?

Now, what about everyone else?  It is more of an expensive toy.  CRMs were developed to prevent hypoglycemia, but in 2024, the FDA approved them for individuals without diabetes.  This is a far bigger market, with estimated sales projected to reach $30 billion in 2030 (1).  This is because the device requires approximately $100 per month in patches to monitor blood glucose levels.  The marketing pitch is that by monitoring your blood glucose level, you can lose weight.  A recent review indicated that any weight loss with CRMs in non-diabetics was not significant (1). 

Even in diabetics, the reduction of HbA1c (the standard marker of severity of diabetes) was only 0.3 percent, which is at the level that the FDA considers to be clinically meaningful.  Keep in mind, the medical definition of being diabetic is having an HbA1c level of greater than 6.5 percent.

For individuals who don’t have diabetes, their problem is hyperinsulinemia, which the CRM doesn’t address.  If you consume excess carbohydrates, the pancreas produces more insulin to lower blood glucose levels.  This means you can have normal blood glucose levels, but now you have excess insulin levels.  This is also known as insulin resistance, which is a major driving force for the development of a wide range of chronic disease conditions, including obesity, diabetes, heart disease, liver disease, kidney disease, infertility, and Alzheimer’s.

Is there a better and less expensive way to control blood sugar levels to lose weight, gain lean body mass, and treat diabetes?  It’s called the Zone diet.  I patented the Zone diet in 2000 to treat hyperinsulinemia (2).  It’s been shown to completely reverse both prediabetes and type 2 diabetes (3, 4, & 5).  In fact, in type 2 diabetics, their HbA1c level decreased by over two percentage points, compared to the 0.3 percent drop that the FDA considers clinically meaningful (5).

Before considering a CRM that costs $100 per month to use, consider following the Zone diet.  You can expect even better results if you add omega-3 fatty acids and polyphenols to the Zone diet.  Why? Each dietary component acts synergistically with the others to activate AMPK, the master regulator of your metabolism. That is the key to a longer and better life (6, 7).      

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Frequently Asked Questions

What is a continuous glucose monitor (CGM)?

A continuous glucose monitor is a wearable device that measures glucose levels in the body throughout the day using a small sensor placed under the skin.

Who should use a CGM?

CGMs are primarily recommended for individuals with type 1 or type 2 diabetes, especially those at risk of hypoglycemia.

Do CGMs help with weight loss?

Current research suggests that CGMs do not lead to significant weight loss in people without diabetes, despite marketing claims.

What is hypoglycemia?

Hypoglycemia is a condition in which blood glucose levels fall too low, causing symptoms such as shakiness, sweating, confusion, seizures, or loss of consciousness.

What is hyperinsulinemia?

Hyperinsulinemia refers to excess insulin levels in the blood, often caused by frequent consumption of high-carbohydrate foods. It is closely linked to insulin resistance.

Why is insulin resistance dangerous?

Insulin resistance can increase the risk of numerous chronic diseases, including obesity, type 2 diabetes, cardiovascular disease, and Alzheimer’s disease.

Is there an alternative to using CGMs for metabolic health?

Dietary strategies such as the Zone Diet, combined with omega-3 fatty acids and polyphenols, may help improve metabolic control by activating AMPK.

References

• 1.   Hutchins KM, Betts JA, Thompson D, Hengist A, Gonzalez JT. Continuous glucose monitor overestimates glycemia, with the magnitude of bias varying by postprandial test and individual – a randomized crossover trial. Am J Clin Nutr. 2025 May;121(5):1025-1034. doi: 10.1016/j.ajcnut.2025.02.024. 
• 2.  Sears, B.  “Method of and nutritional and pharmaceutical compositions for reduction of hyperinsulinemia.”  U.S. Patent No. 6,140,304 (2000)
• 3.  Stentz FB, Brewer A, Wan J, Garber C, Daniels B, Sands C, Kitabchi AE. Remission of pre-diabetes to normal glucose tolerance in obese adults with high protein versus high carbohydrate diet: randomized control trial. BMJ Open Diabetes Res Care. 2016 Oct 26;4(1):e000258. doi: 10.1136/bmjdrc-2016-000258. 
• 4.  Stentz FB, Mikhael A, Kineish O, Christman J, Sands C. High protein diet leads to prediabetes remission and positive changes in incretins and cardiovascular risk factors. Nutr Metab Cardiovasc Dis. 2021 Apr 9;31(4):1227-1237. doi: 10.1016/j.numecd.2020.11.027. 
• 5.  Stentz FB, Lawson D, Tucker S, Christman J, Sands C. Decreased cardiovascular risk factors and inflammation with remission of type 2 diabetes in adults with obesity using a high protein diet: Randomized control trial. Obes Pillars. 2022 Dec 1;4:100047. 
• 6.  Sears B, Saha AK. Dietary control of inflammation and resolution. Front Nutr. 2021 Aug 10;8:709435. doi: 10.3389/fnut.2021.709435. 
• 7.  Sears B, Perry M, Saha AK. Dietary technologies to optimize healing from injury-induced inflammation. Antiinflamm Antiallergy Agents Med Chem. 2021;20(2):123-131. doi: 10.2174/1871523019666200512114210.