Insulin resistance: what it is, and how a blood test measures it

Yes. Fasting glucose can stay in the usual range while insulin output is already elevated, which is why fasting insulin is measured alongside it rather than instead of it.

Fasting insulin with fasting glucose, from which a sensitivity index is calculated, interpreted alongside HbA1c, lipids and liver markers by a doctor.

Often nothing that can be felt. The signs that make a doctor measure it are weight gathering at the waist, dark velvety skin at the neck or armpits, skin tags, irregular periods or PCOS, and strong cravings or sleepiness after meals. None of them confirms it; fasting insulin and glucose do.

One with protein and fibre at every meal: dal, vegetables, curd, eggs or paneer, and whole grains or millets in place of maida and white rice, with few sweet drinks or sweets. A ten to fifteen minute walk after meals helps blood sugar too.

For many people it improves a great deal with less fat around the waist, more muscle, regular activity and better sleep. A doctor reads the results and decides whether anything more is needed, and progress is measured on the same tests rather than guessed.

This page can describe what insulin resistance is and what is measured to detect it. It cannot tell you whether it applies to you. Nothing you can read, and no questionnaire, can — that needs a blood sample and somebody registered to read it against the rest of your results. The one thing this page cannot do is tell you where you actually sit. A panel that includes fasting insulin, read by a registered doctor, can.

• Insulin is the instruction, not the fuel. After a meal the pancreas releases insulin, which tells muscle and liver cells to take glucose out of the blood. Resistance means those cells respond less to the same instruction, so the pancreas sends more of it to get the same job done.
• Blood sugar can stay normal for years while this happens. As long as the pancreas can keep raising output, the glucose reading stays where it always was. This is why an annual check-up that measures only fasting sugar can be entirely reassuring at a point when insulin is already working much harder than it used to.
• It is measurable, and it usually is not measured. Fasting insulin alongside fasting glucose gives a calculable index of sensitivity. It costs very little and is left off nearly every standard Indian health package.
• Weight and insulin resistance run in both directions. Higher fat around the organs is associated with lower insulin sensitivity, and higher circulating insulin is associated with fat being stored rather than released. Which one moved first is generally not knowable in a given person, and it does not change what is worth measuring.
• Direction of cause is genuinely contested in the literature. Anybody telling you confidently which came first for you is guessing.

• That decision may be that no treatment is appropriate. The assessment is what you are buying; a treatment plan is not promised by it.

• You already have a diagnosis of type 1 diabetes — this is a different condition with different care, and it belongs with your treating team.
• You are pregnant or trying to conceive. Metabolic care in pregnancy is specialist work we do not do.
• You are looking for a medicine. No public page in India may discuss prescription-only treatment, and a doctor decides that after seeing results, never before.
• You want a number today. Results take a few days and the reading is a person's judgement, not an instant output.

• ICMR-INDIAB (national study of diabetes and prediabetes in India): Documents a very large prevalence of prediabetes across Indian states, much of it undiagnosed at the time of survey.
• WHO (expert consultation on BMI in Asian populations): Metabolic risk in Asian populations rises at a lower body-mass index than the thresholds derived from European populations.
• HOMA-IR (Matthews et al., the index in ordinary clinical use): Fasting insulin and fasting glucose together estimate insulin sensitivity. It is a population research tool used clinically with judgement, not a pass or fail line.

Metabolic adaptation is the part of this people notice as the plan slowly stopping working.