Insulin is the hormone that tells your cells to absorb glucose from the bloodstream. When cells become resistant to this signal — due to chronic overconsumption, sedentary behaviour, excess visceral fat, and inflammation — your pancreas compensates by producing more insulin. Blood sugar stays normal, but insulin levels are chronically elevated (hyperinsulinemia).
This hidden hyperinsulinemia drives a cascade of problems before blood sugar ever rises: increased fat storage (especially visceral), elevated triglycerides, reduced HDL cholesterol, increased blood pressure, increased inflammation, and accelerated ageing. Insulin resistance is the root mechanism connecting obesity, heart disease, type 2 diabetes, PCOS, non-alcoholic fatty liver disease, and even Alzheimer's (increasingly called 'type 3 diabetes').
The standard blood test for metabolic health is fasting glucose — but glucose is the last thing to rise in insulin resistance. Your pancreas compensates by producing more and more insulin, keeping glucose normal for years or even decades while insulin levels silently climb.
A fasting insulin test or HOMA-IR calculation (fasting insulin × fasting glucose ÷ 405) reveals insulin resistance far earlier than glucose alone. Optimal fasting insulin is under 5 µIU/mL; above 10 suggests emerging resistance. Triglyceride-to-HDL ratio is another accessible proxy: above 2.0 suggests insulin resistance. Yet most doctors only test fasting glucose, missing the 10-20 year window where insulin resistance could be caught and reversed.
Exercise is the most powerful insulin sensitiser known — a single resistance training session can increase insulin sensitivity for 24-48 hours. Regular combination of resistance training and aerobic exercise (especially Zone 2 cardio) dramatically improves insulin signalling. Exercise works by increasing GLUT4 transporter activity in muscle cells, allowing glucose uptake independent of insulin.
Dietary strategies: reduce refined carbohydrates and sugar (the biggest insulin drivers), increase protein and fibre (which blunt insulin spikes), practice time-restricted eating (giving your pancreas regular breaks). Reduce visceral fat through any effective means — even 5-10% body weight loss can dramatically improve insulin sensitivity. Adequate sleep is critical: just 4 nights of poor sleep creates measurable insulin resistance in healthy young adults. Prioritise metabolic health as the foundation of all longevity efforts.
Anyone interested in evidence-based longevity strategies, health optimisation, and understanding the latest research on ageing and healthspan.
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