What insulin resistance is, and why it starts before diabetes
Bijgewerkt 2026-08-07
Deze gids is nog niet in uw taal vertaald en wordt daarom in het Engels getoond.
Kort antwoord
What is insulin resistance?
Insulin resistance means your muscle, liver and fat cells respond weakly to insulin, so the pancreas secretes more of it to get the same job done. Blood glucose can stay in the normal range throughout, because the extra insulin is compensating. That compensation is why the condition is usually silent, and why it is under way before a glucose test shows anything.
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The mechanism, in one paragraph
Insulin is the signal that tells cells to take glucose out of the blood. When those cells respond weakly to the signal, the pancreas compensates by sending more — higher insulin for the same amount of glucose cleared. For a while this works. Glucose readings stay where they should be, and nothing on a standard blood test looks wrong.
The compensation is the whole problem. It is what keeps the condition invisible, and it is what eventually fails: the beta cells that produce insulin cannot keep escalating output indefinitely. When output stops keeping pace with resistance, glucose starts to rise, and only then does a routine test catch it.
Wat het bewijs zegt
Insulin resistance and beta-cell dysfunction are both present before glucose measurements become abnormal.1
Sterk bewijs
How long the run-up actually is
You will often read that insulin resistance precedes diabetes by ten or fifteen years. That figure is not measured; it is inferred. What has actually been measured is narrower, and worth knowing precisely.
A British cohort followed 6,538 civil servants for a median of nearly ten years, testing them repeatedly, and then looked backwards from the 505 who were diagnosed with type 2 diabetes. The trajectories are not gradual. Insulin sensitivity fell steeply across the five years before diagnosis. Fasting glucose drifted slowly, then turned sharply upward about three years out. Beta-cell function rose — the compensation working — and then dropped away in the final years.
So the honest statement is that the detectable deterioration runs for years, not months, and that its steepest part comes late. Whether something subtler is happening a decade earlier is not something that study can tell you.
Wat het bewijs zegt
In a cohort followed for nearly a decade, insulin sensitivity declined steeply during the five years before a type 2 diabetes diagnosis, and fasting glucose rose sharply from about three years before.2
Sterk bewijs
Beta-cell function increased between four and three years before diagnosis, then fell — the compensation succeeding, and then failing.2
Sterk bewijs
Why this matters for what you buy
A glucose sensor measures glucose. It does not measure insulin, and it cannot see the compensation directly. During the years when insulin is climbing and glucose is holding steady, a sensor can show you a perfectly ordinary week.
That is not an argument against wearing one. It is an argument for knowing what a normal-looking trace does and does not rule out, which is the subject of the next guide.
Veelgestelde vragen
- Can I have insulin resistance with a normal HbA1c?
- Yes. Insulin resistance and beta-cell dysfunction are established before glucose measures become abnormal, so a normal HbA1c does not rule it out. It rules out the later stage, not the earlier one.
- Is insulin resistance the same as prediabetes?
- No. Prediabetes is a threshold defined by glucose numbers — a diagnosis you either meet or do not. Insulin resistance is the underlying physiology, and it is present well before those numbers cross the line.
- Does a glucose sensor measure insulin resistance?
- No. A CGM measures interstitial glucose. Insulin is not measured by any consumer wearable currently sold. Estimating resistance requires a blood test that measures insulin alongside glucose.
Literatuur
- 1.Tabák AG, Herder C, Rathmann W, Brunner EJ, Kivimäki M (2012). Prediabetes: a high-risk state for diabetes development. The Lancet. 10.1016/S0140-6736(12)60283-9
- 2.Tabák AG, Jokela M, Akbaraly TN, Brunner EJ, Kivimäki M, Witte DR (2009). Trajectories of glycaemia, insulin sensitivity, and insulin secretion before diagnosis of type 2 diabetes: an analysis from the Whitehall II study. The Lancet. 10.1016/S0140-6736(09)60619-X