Hyperinsulinemia: Unmasking the Silent Driver of Chronic Disease

NOTE: This article was originally posted on December 5, 2018, and was updated and reposted on February 22, 2026. 

Introduction

Insulin resistance and hyperinsulinemia are often lumped together, but they are different conditions that work in a cycle. To understand the risk they pose, we first have to look at how the body manages energy.

Normally, blood glucose (also called “blood sugar”) is tightly regulated between 3.9–5.5 mmol/L (70–100 mg/dl). When someone eats, their blood sugar rises as the body breaks down carbohydrates. This triggers the hormone insulin to be released from the beta cells of the pancreas. Think of insulin as a key that signals the muscle and fat cells to unlock and enable sugar to move out of the blood, so that it can be used for energy.

• Hyperinsulinemia literally means “too much insulin.” It occurs when the beta-cells of the pancreas secrete too much of the hormone. While this can happen in response to high blood sugar (hyperglycemia), as I wrote about in this 2018 article, we have known for almost a decade that chronically elevated levels of insulin often come before abnormal blood sugar levels [1][2][3].

• Insulin resistance occurs when the cells of the body stop responding to insulin signals. When the body is flooded with too much insulin for too long, the cells “lock the doors” to protect the body from being overwhelmed by too much glucose. As a result, that glucose remains in the blood, causing hyperglycemia (which means “too much glucose”).

When someone is insulin resistant, the sugar stays in the blood longer than it should, and this creates a cycle. The beta cells of the pancreas pump out even more insulin to try to force the excess sugar into the cells, which only makes the resistance worse. Over time, this “silent” cycle of high insulin and resistance becomes the primary driver for many of the chronic diseases we see today.

Diseases Associated with Hyperinsulinemia

Current research has shifted the focus from hyperglycemia (high blood sugar) as the primary driver of disease to the structural and functional damage caused by hyperinsulinemia (high levels of circulating insulin).

Below is a list of diseases now recognized as being driven by chronic hyperinsulinemia:

Heart Disease

High insulin is considered to be a silent trigger for heart disease. It causes the heart muscle to thicken and stiffen, leading to a condition known as ‘heart failure with preserved left ventricular ejection fraction (HFpEF)’ that can occur even when blood sugar levels still appear normal [4].

Reproductive Health (PCOS)

As I wrote about in this 2026 article, hyperinsulinemia is now considered the upstream driver of Polycystic Ovarian Syndrome (PCOS). It is the high insulin levels that signal the ovaries to produce excess testosterone, creating a cycle that worsens both metabolic and reproductive symptoms [5].

Fatty Liver Disease (MASLD)

Metabolically Dysfunctional-Associated Steatotic Liver Disease (MASLD), previously known as Non-Alcoholic Fatty Liver Disease (NAFLD), is a condition driven by insulin’s signal to the liver to create and store fat. High insulin levels promote “de novo lipogenesis” (the creation of new fat), leading to inflammation and permanent liver scarring [6].

Alzheimer’s (Type 3 Diabetes)

As I wrote about in this 2018 article, Alzheimer’s disease is often referred to as type 3 diabetes (T3D) because it is characterized by chronic insulin resistance of the brain. This leads to inflammation, oxidative stress, dysfunction in intercellular communication, and neuronal cell death. These processes are what contribute to cognitive decline in neurodegenerative disorders such as Alzheimer’s disease. 

Obesity

There is strong evidence to support the idea that hyperinsulinemia is a key factor in obesity [8]. The over secretion of insulin, even at normal glucose levels, may lower blood glucose even further, stimulating eating

Insulin is a potent growth-promoting hormone. When levels are chronically high, it can act as “fertilizer” for tumors, specifically increasing the risk and progression of colorectal, breast, and pancreatic cancers by signaling cells to divide rapidly [8].

Type 2 Diabetes

Hyperinsulinemia resulting from chronic overnutrition acts as the primary driver of type 2 diabetes by forcing the body to store fat inside organs, including the liver and the pancreas. Continually high levels of insulin cause the liver and muscle cells to become “deaf” to insulin, resulting in the insulin resistance that drives the progression of type 2 diabetes [9].

Some final thoughts…

Insulin resistance and hyperinsulinemia are the foundational drivers of chronic disease. Current clinical evidence supports that it is not simply a matter that the body fails to use insulin, but that muscle and liver cells become resistant to insulin as a protective mechanism in response to a constant overabundance of the hormone.

By the time blood glucose levels rise high enough to be seen as abnormal on a standard lab test, the cycle of hyperinsulinemia has been causing structural and functional damage to the body for years. Since hyperinsulinemia is the primary driver of several metabolic diseases, it is also the primary target for dietary strategies that address the underlying hyperinsulinemia, rather than only managing blood glucose.

More Info

I have almost a decade of experience helping people lower high levels of circulating insulin, as well as blood sugar. Learn about me and the Comprehensive Dietary Package that I offer.

To your good health!

Joy

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References

1. Crofts, C., Understanding and Diagnosing Hyperinsulinemia. 2015, AUT University: Auckland, New Zealand. p. 205.
2. Crofts CAP, Z.C., Wheldon MC, et al, Hyperinsulinemia: a unifying theory of chronic disease? Diabesity, 2015. 1(4): p. 34-43.
3. Crofts, C., et al., Identifying hyperinsulinaemia in the absence of impaired glucose tolerance: An examination of the Kraft database. Diabetes Res Clin Pract, 2016. 118: p. 50-7.
4. Fazio S and Carlomagno G (2026) Insulin resistance with associated hyperinsulinemia as a risk factor for the development and worsening of HFpEF. Front. Cardiovasc. Med. 13:1719492. doi: 10.3389/fcvm.2026.1719492
5. Houston EJ, Templeman NM. Reappraising the relationship between hyperinsulinemia and insulin resistance in PCOS. J Endocrinol. 2025 Mar 12;265(2):e240269. doi: 10.1530/JOE-24-0269. PMID: 40013621; PMCID: PMC11906131.
6. Bae JC. Metabolic Dysfunction-Associated Steatotic Liver Disease: The Role of Hepatic Steatosis in Insulin Resistance and Metabolic Health. Endocrinol Metab (Seoul). 2025 Apr;40(2):304-306. doi: 10.3803/EnM.2025.2340. Epub 2025 Mar 24. PMID: 40123045; PMCID: PMC12061749.
7. Chapple B, Bayliss E, Woodfin S, Smith M, Winter J, Moore W. Type 3 Diabetes: Linking Insulin Resistance to Cognitive Decline. Diseases. 2025; 13(11):359. https://doi.org/10.3390/diseases13110359
8. Thomas, D.D.; Corkey, B.E.; Istfan, N.W.; Apovian, C.M. Hyperinsulinemia: An Early Indicator of Metabolic Dysfunction. J. Endocr. Soc. 2019, 3, 1727–1747.
9. Janssen JAMJL. Overnutrition, Hyperinsulinemia and Ectopic Fat: It Is Time for A Paradigm Shift in the Management of Type 2 Diabetes. International Journal of Molecular Sciences. 2024; 25(10):5488. https://doi.org/10.3390/ijms25105488

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