Insulin and Insulin Resistance

Let’s start with a simple introduction to insulin and insulin resistance.

Insulin is one of the body’s most important hormones for regulating blood sugar and managing how energy is used and stored. When we eat rice, pasta, sweets, and other carbohydrate-containing foods, digestible carbohydrates are broken down into simple sugars such as glucose and absorbed into the bloodstream. As blood glucose rises, the pancreas releases insulin.

You can think of insulin as an “energy management signal.” It tells tissues such as muscle, fat, and the liver that more glucose is available in the blood and that this energy now needs to be used or stored appropriately.

In muscle, insulin helps glucose enter cells, where it can be used for energy or stored as glycogen. In the liver, insulin promotes glycogen storage and reduces the release of excess glucose into the bloodstream. In fat tissue, insulin promotes energy storage and suppresses excessive fat breakdown.

Together, these actions help keep blood glucose within a relatively stable range.

What is insulin resistance? Simply put, it means that the body becomes less responsive to insulin’s signal. Normally, a certain amount of insulin is enough to produce an effective response. But when insulin sensitivity decreases, the same amount of insulin no longer has the same effect. To keep blood glucose under control, the pancreas has to produce more insulin to compensate. [1]

This is why insulin resistance can be easy to miss in its early stages: blood glucose may still look normal, while insulin levels have already started to rise. In other words, normal fasting glucose or HbA1c does not necessarily mean that insulin metabolism is completely normal.

If factors such as excess energy intake, increased visceral fat, physical inactivity, poor sleep, or genetic susceptibility persist, insulin resistance may gradually worsen. The body then needs to produce even more insulin to maintain normal blood glucose. When the pancreas can no longer compensate adequately, blood glucose may begin to rise, potentially progressing to prediabetes and eventually type 2 diabetes. [1]

Insulin resistance therefore often begins before obvious high blood sugar appears. In many people, the body may remain in a state of compensatory hyperinsulinemia for a considerable period before glucose levels become clearly abnormal. This is why insulin resistance should not be assessed by blood glucose alone, but as part of the overall metabolic picture.

This article provides general information and does not replace medical assessment, diagnosis or treatment.