Metabolic health, Johannesburg
Insulin resistance and metabolic health in Johannesburg.
Doctor-led assessment of metabolic health, including glucose regulation, body composition and cardiometabolic risk, using established diagnostic criteria rather than a single score.
In short
Insulin resistance describes reduced responsiveness to insulin in tissues such as muscle, liver and adipose tissue. It often accompanies visceral adiposity, raised blood pressure, dyslipidaemia and fatty liver, but there is no single universally accepted clinical blood test that diagnoses insulin resistance in routine practice. Prediabetes and diabetes are diagnosed using established fasting glucose, HbA1c and oral glucose tolerance test criteria. Fasting insulin or HOMA-IR may add context in selected patients, but they are not diagnostic gold standards and should not be presented as such.
Medically reviewed by Dr Arnav Kapur, MBBCh Cum Laude
The approach
Understand first. Then treat.
Insulin moves glucose out of the bloodstream and into tissues. When those tissues respond less well, the pancreas compensates by producing more insulin, and blood glucose can stay normal for years. This is why people are often told their sugar is fine while their metabolic risk is already rising.
Assessing metabolic health therefore means looking at the whole cluster rather than one marker: waist and body composition, blood pressure, lipids, glucose and HbA1c, liver markers, sleep, medication and family history. Where a fasting insulin or HOMA-IR is measured, it is used as supporting context within that picture, not as a diagnosis on its own.
What a metabolic health assessment covers
- Full medical, family, medication and lifestyle history
- Weight, waist measurement and body composition, including visceral fat estimation
- Blood pressure
- Fasting glucose and HbA1c, with an oral glucose tolerance test where indicated
- Full lipid panel, including triglycerides and HDL cholesterol
- Liver enzymes and assessment for metabolic dysfunction-associated steatotic liver disease where relevant
- Fasting insulin or HOMA-IR in selected cases, interpreted as context rather than diagnosis
- Thyroid function and other endocrine contributors where the history suggests them
- Sleep quality and screening for sleep-disordered breathing where appropriate
- Cardiovascular risk estimation, including ApoB or lipoprotein(a) where useful
What insulin resistance means
Insulin resistance is a physiological state, not a formal diagnosis with a single confirmatory test. Muscle takes up less glucose, the liver continues releasing glucose when it should not, and adipose tissue handles fat less well. Research settings measure it with clamp studies, which are not practical clinically. In everyday practice it is recognised from a pattern: central adiposity, raised triglycerides, lower HDL cholesterol, raised blood pressure, fatty liver and glucose values drifting upwards.
Why normal fasting glucose can coexist with metabolic risk
Fasting glucose is defended tightly. Higher insulin output can keep it within range long after insulin sensitivity has fallen, and post-meal glucose usually rises first. HbA1c can also sit in the normal range early on. So a normal fasting glucose is reassuring about diabetes at that moment, but it does not confirm healthy metabolism. This is why waist measurement, triglycerides, HDL cholesterol, blood pressure and liver markers matter alongside it, and why an oral glucose tolerance test is sometimes the test that clarifies things.
How we assess metabolic health
Assessment starts with history, examination, blood pressure, waist measurement and body composition, then established laboratory testing: fasting glucose, HbA1c, lipids and liver enzymes, with an oral glucose tolerance test where prediabetes or gestational risk needs clarifying. Diagnosis of prediabetes or diabetes follows recognised criteria. Fasting insulin and HOMA-IR are added selectively, for example when explaining why metabolic risk is present despite acceptable glucose, and are interpreted with the knowledge that insulin assays vary between laboratories and that no agreed clinical cut-off defines insulin resistance.
What improves insulin sensitivity
The measures with the strongest evidence are unglamorous and effective. Weight loss where excess weight is present, particularly loss of visceral fat, improves insulin sensitivity substantially. Resistance training increases muscle glucose disposal, and regular aerobic activity adds independent benefit. Adequate sleep and treatment of sleep apnoea matter more than most people expect. Nutrition changes that reduce refined carbohydrate and alcohol intake and raise protein and fibre help. Where risk is high or glucose is already abnormal, medication such as metformin, or GLP-1-based therapy for appropriate weight management, may be indicated. Structured prevention programmes reduce progression to type 2 diabetes.
Common questions
Answers before you book.
Can I have insulin resistance with a normal HbA1c?
Yes. HbA1c reflects average glucose over roughly three months, and higher insulin output can keep glucose normal for years while insulin sensitivity falls. A normal HbA1c makes diabetes unlikely at that point, but it does not exclude insulin resistance or the cardiometabolic risk that travels with it.
Is fasting insulin or HOMA-IR diagnostic?
No. Neither is an accepted diagnostic test for insulin resistance in routine practice. Insulin assays differ between laboratories, results vary from day to day and there is no agreed clinical threshold. They can be informative in selected patients as part of a wider assessment, but a raised HOMA-IR is not a diagnosis and a normal one is not an all-clear.
Does insulin resistance cause weight gain?
The relationship runs in both directions and is not fully settled. Excess visceral fat clearly worsens insulin resistance, and insulin resistance in turn makes weight management harder. Treating it as the sole cause of weight gain oversimplifies it; other factors including sleep, medication, hormonal conditions, nutrition and activity all contribute.
Can insulin resistance be reversed or improved?
It can usually be improved, often substantially, and prediabetes can revert to normal glucose regulation in many people. Weight loss where appropriate, resistance and aerobic training, better sleep, improved nutrition and medication where indicated all contribute. How much improvement is achievable depends on the starting point, duration and individual factors.
This page provides general health information and does not replace individual medical assessment. Diagnosis of prediabetes or diabetes follows established criteria, and investigations and treatment are selected according to your medical history and clinical findings.
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Centre of Advanced Medicine, 13 Scott St, Waverley, Johannesburg
Monday to Friday, 07:40 to 17:00
011 440 8721