Discovery
In 1936 Harold Himsworth gave patients glucose plus insulin and saw some respond briskly while others barely changed, splitting diabetes into insulin-sensitive and insensitive types (Himsworth, 1936). DeFronzo's team formalized the glucose clamp in 1979, and Gerald Reaven's 1988 Banting lecture tied insulin resistance to high blood pressure and lipids as 'Syndrome X,' the forerunner of metabolic syndrome.
What happens inside
Fat building up in the liver and muscle disrupts insulin signaling (Samuel & Shulman, 2012), so the pancreas works overtime. When beta cells tire, prediabetes and type 2 diabetes follow. It is closely tied to fatty liver and PCOS.
Signs and tests
Most people feel nothing. Clues include a larger waist, dark velvety skin on the neck (acanthosis nigricans), high blood pressure and triglycerides, and borderline glucose or HbA1c (NIDDK, n.d.). HOMA-IR = fasting glucose (mg/dL) × fasting insulin ÷ 405 (Matthews et al., 1985), but cut-offs vary by population and lab.
Reversing it
In the Diabetes Prevention Program, a 7% weight-loss goal plus 150 minutes of weekly activity cut diabetes incidence by 58%, versus 31% with metformin (DPP Research Group, 2002). Combine aerobic and strength training, cut refined carbs and sugary drinks, and protect sleep. Lean people, especially East Asians, can still be insulin resistant if they carry visceral fat or little muscle.
This article is general health information and is not a substitute for diagnosis or treatment. If symptoms persist, see a doctor.
FAQ
- Does insulin resistance mean I have diabetes?
- No. It often comes years earlier; blood sugar may stay normal while the pancreas compensates.
- What exercise works best?
- A mix of aerobic activity (about 150 minutes a week) and strength training twice a week; check with your doctor if you have conditions.
Sources reviewed: 2026-11-02
References
- Himsworth, H. P. (1936). Diabetes mellitus: Its differentiation into insulin-sensitive and insulin-insensitive types. The Lancet, 227(5864), 127–130. The first split of diabetes into insulin-sensitive and insensitive types.
- DeFronzo, R. A., Tobin, J. D., & Andres, R. (1979). Glucose clamp technique: A method for quantifying insulin secretion and resistance. American Journal of Physiology, 237(3), E214–E223. The clamp, the gold-standard measure.
- Matthews, D. R., Hosker, J. P., Rudenski, A. S., Naylor, B. A., Treacher, D. F., & Turner, R. C. (1985). Homeostasis model assessment: Insulin resistance and β-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia, 28(7), 412–419. Introduced HOMA-IR from fasting glucose and insulin.
- Reaven, G. M. (1988). Role of insulin resistance in human disease. Diabetes, 37(12), 1595–1607. The Banting lecture proposing Syndrome X.
- Diabetes Prevention Program Research Group. (2002). Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. The New England Journal of Medicine, 346(6), 393–403. Lifestyle change cut diabetes incidence by 58%.
- Samuel, V. T., & Shulman, G. I. (2012). Mechanisms for insulin resistance: Common threads and missing links. Cell, 148(5), 852–871. Review of how ectopic fat blocks insulin signaling.
- National Institute of Diabetes and Digestive and Kidney Diseases. (n.d.). Insulin resistance & prediabetes. NIH patient guide to signs, risks and prevention.