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A fasting sugar of 92 and an HbA1c of 5.6% read as normal on any Indian lab report. They can also belong to someone whose pancreas is pouring out far more insulin than usual to hold them there. That is insulin resistance, and in the Whitehall II study it was visible for about five years before type 2 diabetes was diagnosed.
In a Finnish trial, overweight adults with impaired glucose tolerance who lost about 4 kg saw 11% develop diabetes in four years, against 23% of the comparison group. A fasting insulin test is worth asking for when sugar is normal but your waist or family history is not. Not everyone with insulin resistance goes on to diabetes.
A normal sugar report can hide years of insulin resistance
Insulin resistance describes how your tissues respond to insulin. Type 2 diabetes is a diagnosis made from blood sugar once it crosses a fixed line. After a plate of rice and rajma, glucose floods the blood and the pancreas releases insulin, which lets muscle and liver take the glucose in. When those tissues respond poorly, the pancreas simply makes more.
A Lancet review (Kahn) lays out what follows. While the beta cells can step up their output, glucose stays normal. It rises only once they can no longer release enough. So two colleagues in the same office can both have a fasting sugar of 92 and be in very different places. In one the pancreas is coasting; in the other it is pouring out far more insulin to hold that reading steady.
Whitehall II shows the timing. The study tested British civil servants every few years for more than a decade, and the researchers (Tabák) traced the numbers of the 505 who developed diabetes. Insulin sensitivity fell steeply over the five years before diagnosis. Insulin output actually rose three to four years before, then began to fail, and in the last three years fasting and two-hour glucose climbed fast.
Laid out as a timeline, there were several years when insulin was high and sugar was still normal or only slightly raised. That stretch is when changes to weight, food and activity have the most room to work, because the beta cells are still in good shape.
Why do so many Indians go from insulin resistance to diabetes?
The ICMR-INDIAB study tested 113,043 adults across every state (Anjana) and found 11.4% with diabetes and another 15.3% with prediabetes. Almost four in ten had abdominal obesity, the belly fat most closely tied to insulin resistance.
South Asians also develop diabetes at lower body weights than white populations, as a Diabetes Care review set out (Gujral). Many Indians carry more fat in the abdomen and liver, and less muscle, at the same BMI. A man with a BMI of 24 and a thick waist can be more insulin resistant than a European with a BMI of 28.
A British pair of researchers (Taylor and Holman) proposed a personal fat threshold. Above it, fat overflows into the liver and pancreas and diabetes becomes likely, whatever the BMI chart says. For many Indians that threshold seems to sit low, which is why diabetes so often arrives in people who never thought of themselves as overweight.
Check it yourself in 2 minutes: five lines on your report and one tape measure
Take your last blood report and find fasting glucose and HbA1c first. The American Diabetes Association calls a fasting glucose of 100–125 mg/dL, or an HbA1c of 5.7–6.4%, prediabetes. Diabetes is a fasting glucose at or above 126 mg/dL or an HbA1c at or above 6.5%, usually confirmed on a second test.
Then look for three lines many reports skip: fasting insulin, triglycerides and HDL. High triglycerides beside a low HDL often travel with insulin resistance, and a fasting insulin above the lab's range shows a pancreas working overtime. If fasting insulin was never tested, that is worth noting too.
Finally, measure your waist midway between the lowest rib and the top of the hip bone, after breathing out. For Asian Indians, more than 90 cm in men or 80 cm in women counts as abdominal obesity (Misra), even when the BMI looks fine. A normal sugar, a waist above the line and a parent with diabetes together are a good reason to ask for fasting insulin.
Labs measure insulin in slightly different ways and there is no single agreed cut-off, so a doctor reads it with the sugar results, the waist and the family history. A two-hour glucose tolerance test can also catch the after-meal spike that fasting tests miss.
Can you stop insulin resistance from becoming type 2 diabetes?
Often you can. The Finnish Diabetes Prevention Study (Tuomilehto) enrolled 522 overweight middle-aged adults whose glucose tolerance was already impaired. Half got regular, personal advice on losing weight, eating less fat and more fibre, and moving more. They lost about 4 kg in the first year. Four years later, 11% of them had diabetes, against 23% of the group left to carry on as usual.
Muscle counts as much as weight, because it is where most of the glucose from a meal ends up. In a survey of 13,644 American adults (Srikanthan), each 10% more muscle relative to body weight went with 11% lower HOMA-IR and 12% lower odds of prediabetes or diabetes. It is an association from one survey, though it fits what strength-training trials show.
At an Indian table, most of the change is in proportions and order. Put half the usual rice on the plate and fill the rest with dal, a second sabzi or curd, and mix besan or jowar into the roti atta. In a small New York study of adults with type 2 diabetes (Shukla), eating vegetables and protein before the carbohydrate lowered both glucose and insulin after the meal.
Start the day with protein: two eggs with a roti, besan chilla with curd, or sprouts with paneer, rather than poha with sweet chai and biscuits. Make dinner the lightest meal, finish it two or three hours before bed, and walk for ten or fifteen minutes afterwards, because working muscles soak up glucose. Fruit is fine whole; juice and dried-fruit laddoos behave like sugar.
Does losing weight help once type 2 diabetes has started?
It helps a great deal, and early on it can lead to remission. A Newcastle team (Lim and Taylor) put 11 adults with type 2 diabetes on a supervised 600-calorie diet for eight weeks. Fasting glucose came down to normal within a week, liver fat fell from 12.8% to 2.9%, and the beta cells' first burst of insulin recovered towards normal. A diet that steep is only safe with a medical team adjusting treatment as you go.
The DiRECT trial (Lean) tested the idea in ordinary GP surgeries in Scotland and north-east England. Remission meant an HbA1c below 6.5% after at least two months off all glucose-lowering treatment. At 12 months, 46% of the weight-management group reached it, against 4% of the control group, and remission reached 86% among those who lost 15 kg or more.
Remission still needs watching. Sugar can climb again if the weight returns, so yearly checks of HbA1c, kidneys, eyes, feet, blood pressure and cholesterol carry on, and many people need treatment alongside lifestyle change. What is lost matters as well. A doctor-led plan that starts with a home blood test can aim at losing up to 20% of body weight while keeping muscle. That combination lowers insulin resistance and clears fat from the liver and pancreas.
A goal small enough to keep, shared with the family, does most of the work
The Finnish volunteers lost only a few kilos and moved on most days, and their diabetes risk fell by more than half. That is a useful benchmark: 5–10% of body weight over a year and protein at every meal. Add the WHO's 150–300 minutes a week of moderate activity such as brisk walking, with muscle-strengthening work on two or more days.
Ask your doctor when to repeat the tests. HbA1c averages about three months of sugar, so a flat reading at six weeks is no reason to give up on a routine that is working.
Insulin resistance runs in families, through shared food, routines and genes. If a parent has diabetes, brothers, sisters and grown-up children are worth testing too, slim or not. In most Indian homes one cook feeds everyone, so a lighter, higher-protein dinner for the whole table is far easier to keep up than one person eating separately.