36-year-old has high blood sugar despite watching fasting insulin: What went wrong?

This is becoming increasingly common. Over the last two years, fasting insulin has become the new buzzword in metabolic health discussions online. Influencers often describe it as the hidden truth behind obesity, diabetes, fatty liver, and even aging itself. Many people now believe that a single fasting insulin number can reveal future diabetes risk more accurately than traditional tests.

Understanding insulin

The reality is far more complicated. Insulin is unquestionably an important hormone. It helps glucose move from blood into tissues and plays a central role in metabolism. In people with obesity, fatty liver, metabolic syndrome, or polycystic ovary syndrome, insulin resistance may develop years before overt diabetes appears. During this stage, the body compensates by producing larger amounts of insulin to maintain near-normal blood glucose levels.

So yes, elevated fasting insulin can sometimes suggest underlying insulin resistance. But that does not mean fasting insulin is a scientifically standardized routine monitoring test. Someone may have a “normal” fasting insulin but still experience major post-meal glucose spikes — something better detected through postprandial glucose checks.

Unlike HbA1c or blood glucose measurements, insulin assays vary considerably between laboratories. Results fluctuate with sleep, stress, exercise, recent diet, obesity, and even the timing of the test. More importantly, there are no universally accepted cut-offs for defining insulin resistance in routine clinical practice. Two laboratories may produce different “normal ranges” for the same individual. This is why major diabetes guidelines do not currently recommend fasting insulin as a routine monitoring tool. In fact, people are often ignoring far more meaningful metabolic markers.

What markers, tests should guide your treatment

HbA1c, despite all the criticism it receives online, remains one of the most validated diabetes tests available. It reflects average blood glucose over roughly three months and predicts long term diabetes complications reasonably well. But modern diabetes care is no longer limited to HbA1c alone.

Doctors increasingly use self-monitoring of blood glucose, or SMBG, using glucometers to understand fasting and post meal glucose patterns in real life. Post meal spikes are particularly important in Indians, who often develop exaggerated glucose excursions after carbohydrate-rich meals even before HbA1c rises substantially. There is the oral glucose tolerance test (OGTT), which requires drinking a sugary liquid and having your blood drawn at intervals over 1 to 3 hours to see how efficiently your body processes the sugar.

Continuous glucose monitoring systems, or CGMS, have added another layer of sophistication, especially in people with diabetes. These wearable sensors track glucose continuously through the day and night, helping identify hidden post-meal spikes, nocturnal hypoglycaemia, glucose variability and “time in range.” Two people with identical HbA1c values may have completely different glucose profiles when monitored continuously.

Why diabetes management is not just about blood sugar

At the same time, diabetes treatment itself has evolved beyond simply lowering blood glucose. Newer medicines such as GLP-1 receptor agonists and SGLT2 inhibitors are changing the entire philosophy of diabetes care. These drugs can reduce cardiovascular risk, protect kidney function, promote weight reduction and improve fatty liver disease in selected individuals. Increasingly, doctors are looking beyond glucose alone and focusing on the broader metabolic picture.

The broader picture includes weight, waist circumference, triglycerides, LDL and HDL cholesterol, liver health, blood pressure, sleep quality, dietary habits and physical activity — all of which often provide more clinically useful information than a fasting insulin number in isolation.

For Karan, the solution ultimately had little to do with chasing insulin levels. He needed weight reduction, improved sleep, more physical activity, dietary restructuring, and long-term metabolic risk reduction. His treatment plan would have been almost identical whether his fasting insulin was moderately elevated or not.

That is perhaps the most important message in today’s era of social media driven health advice. Do not chase fashionable biomarkers. Blood sugar is about understanding the entire metabolic system of the patient. Fasting insulin is not the magic answer either.

(Dr Bhattacharya is an endocrinologist at Apollo Hospital, New Delhi)