Insulin Resistance: The Signs Before Diabetes

Insulin resistance develops years before blood sugar rises, which is why a normal glucose result is not reassurance on its own. The signs are mostly indirect: a growing waist, dark velvety skin folds, high triglycerides with low HDL, and fatty liver — and in South Asians it appears at lower body weights.

What it is, briefly

Insulin moves glucose from the blood into cells. In insulin resistance the cells respond less readily, so the pancreas compensates by producing more insulin. For a long time this works: glucose stays normal because insulin levels are high.

That compensation is why standard tests look fine for years. Fasting glucose and even HbA1c can sit in the normal range while insulin is running high and the underlying problem progresses.

Eventually the pancreas cannot keep up, glucose starts to rise, and prediabetes appears, then type 2 diabetes. By the time a glucose test flags the problem, the process has typically been under way for years.

That is the case for recognising the earlier signs, because this is the stage at which it is most reversible. whether prediabetes can be reversed covers the next stage along.

The signs worth knowing

Acanthosis nigricans is worth knowing about because people assume it is dirt or poor hygiene and scrub at it. It is a skin manifestation of high insulin, and its appearance on the back of the neck is a genuine prompt to get glucose and lipids checked.

The lipid signature is the one most often sitting unread in someone's file: high triglycerides with low HDL, as what raises triglycerides and raising HDL describe, is close to a fingerprint for this.

Why South Asians get it earlier

South Asians develop insulin resistance, type 2 diabetes and cardiovascular disease at lower BMI and younger ages than European populations. This is well documented and it changes what the thresholds should be.

The usual explanation involves body composition: at the same BMI, South Asians tend to carry more visceral fat and less muscle, and visceral fat drives insulin resistance disproportionately. The thin-outside-fat-inside pattern is the practical consequence — a normal BMI with a high waist and a metabolic picture that does not match the appearance.

This is why Indian BMI thresholds are set lower, at 23 for overweight and 25 for obesity rather than 25 and 30, and why waist matters more than weight. BMI thresholds for Indians, waist versus weight and why South Asians get heart disease earlier cover it.

The practical implication: being slim is not reassurance. A slim person with a waist over the threshold, a fatty liver and high triglycerides has insulin resistance regardless of what the scale says.

How it is actually measured

There is no single routine test, which is part of why it goes unrecognised.

• Fasting insulin with fasting glucose (HOMA-IR) — the usual research measure; available but not routine, and assays vary.
• Fasting glucose — normal until late, so a poor early marker.
• HbA1c — same limitation, plus the anaemia confounder per what HbA1c measures.
• Oral glucose tolerance test — picks up post-load problems earlier than fasting glucose does.
• Triglyceride-to-HDL ratio — a crude but useful and essentially free proxy from a standard lipid profile.
• Waist circumference — the cheapest marker of all, and better than BMI.

For most people the sensible package is a fasting glucose or HbA1c, a lipid profile, liver enzymes, blood pressure and a waist measurement. That combination detects the cluster without needing a specialist test, and it is what you can reasonably ask a GP for.

What reverses it

The encouraging part: insulin resistance responds well to the things that are available to everyone, and at this stage the response is often substantial.

• Losing excess weight, especially visceral — the largest single lever.
• Resistance training — muscle is the main site of glucose disposal, so more of it helps directly.
• Aerobic exercise — improves insulin sensitivity for up to a couple of days after a session, which is an argument for frequency.
• Cutting sugary drinks and refined carbohydrate — direct effect on the liver.
• More fibre and protein at meals — flattens the glucose curve, per why blood sugar spikes after Indian meals.
• Sleep — even a few nights of short sleep measurably worsens insulin sensitivity.
• Treating fatty liver — the two improve together, per reversing fatty liver.

The exercise point is underrated. A single session improves insulin sensitivity for a day or two, so three or four sessions a week keeps you in an improved state most of the time. Frequency beats duration for this particular outcome.

When to see a doctor

If you have acanthosis nigricans, a waist above the Indian thresholds, a lipid profile showing high triglycerides with low HDL, fatty liver on an ultrasound, or PCOS, it is worth asking specifically about insulin resistance and getting glucose, lipids, liver enzymes and blood pressure checked together.

Also if there is type 2 diabetes in a parent or sibling, which raises your risk substantially and brings forward the age at which screening is sensible.

And see a doctor promptly for symptoms of actual diabetes — excessive thirst, frequent urination, unexplained weight loss, blurred vision, recurrent infections or slow-healing wounds. Those are not early signs; they indicate the process has already progressed.

Where KABO fits in

The things that reverse insulin resistance are weight loss, resistance training, frequent aerobic exercise and less refined carbohydrate. A shake does none of them.

What it can do is make the protein target easier while you are doing those things, which matters because muscle is where glucose is disposed of and protein protects muscle in a deficit. A serving carries 25 g of complete plant protein with 26 vitamins and minerals. Get the tests the article lists before changing anything.

Frequently asked questions

What are the first signs of insulin resistance?

Mostly indirect: a growing waist, dark velvety skin on the neck or armpits, high triglycerides with low HDL on a lipid profile, and fatty liver found incidentally. Blood sugar stays normal until late.

Can you be slim and insulin resistant?

Yes, and it is common in South Asians. At the same BMI, South Asians tend to carry more visceral fat and less muscle, so a normal weight with a high waist can accompany genuine insulin resistance.

What is the dark skin on my neck?

Possibly acanthosis nigricans, a skin sign of high insulin. It is not dirt and does not scrub off. It is a reasonable prompt to have glucose and lipids checked.

Is insulin resistance reversible?

Often substantially, particularly before diabetes develops. Weight loss, resistance training, frequent aerobic exercise, less refined carbohydrate and adequate sleep all improve it.

Sources

• World Health Organization, cardiovascular disease and healthy diet fact sheets. who.int
• ICMR-NIN, Dietary Guidelines for Indians (2024). nin.res.in
• National Institutes of Health, Office of Dietary Supplements. ods.od.nih.gov