- Blood sugar testing reveals how well the body is regulating glucose — a critical indicator of metabolic health
- Obesity, particularly central (abdominal) obesity, causes insulin resistance — the body stops responding properly to its own insulin
- Prediabetes (elevated blood sugars that don't yet meet the diabetes threshold) can be detected years before Type 2 Diabetes develops
- Two distinct forms of prediabetes exist: Impaired Glucose Tolerance (IGT) and Impaired Fasting Glucose (IFG)
- MedSurg Weight Loss screens for diabetes and prediabetes as part of every metabolic assessment — and can support treatment to prevent progression
How the Body Normally Regulates Blood Sugar
When we eat a meal, carbohydrates are broken down into glucose, which enters the bloodstream. The pancreas detects this rise in blood glucose and releases the hormone insulin in response. Insulin acts as a key — unlocking cells throughout the body to allow glucose to enter and be stored or used for energy.
Carbohydrates are digested into glucose, which enters the bloodstream — raising blood glucose levels.
In response to rising blood glucose, the pancreas releases insulin — signalling the body's cells to absorb glucose from the bloodstream.
Cells in the liver, muscle, and fat tissue take up glucose from the blood — lowering blood sugar back to a safe range. Too much glucose in the blood is damaging to blood vessels and organs.
How Obesity Disrupts This System
Obesity — particularly central (abdominal) obesity — places significant strain on this regulatory system. Excess visceral fat interferes with insulin signalling throughout the body, causing cells to become resistant to insulin's effects. The pancreas compensates by producing more and more insulin, but over time it can no longer keep up with demand.
The result is persistently elevated blood glucose levels — first in the prediabetic range, and eventually meeting the threshold for Type 2 Diabetes. This process can unfold over many years, silently, without any noticeable symptoms.
Understanding Prediabetes — IGT and IFG
Before blood sugar levels reach the diagnostic threshold for Type 2 Diabetes, they often pass through a zone called prediabetes — detectable on blood testing years before diabetes develops. This is a critical window for intervention. There are two clinically recognised forms:
Blood glucose levels are higher than normal after eating — the body struggles to clear the glucose load from a meal within the expected time. Detected on an Oral Glucose Tolerance Test (OGTT).
Blood glucose levels are elevated in the fasting state — even without food, the body is unable to keep glucose within the normal range. Detected on a fasting blood glucose test.
Blood Glucose Reference Ranges
The following thresholds are used in Australian clinical practice to classify blood glucose results:
| Category | Fasting glucose | 2-hr post-load glucose | HbA1c |
|---|---|---|---|
| Normal | < 6.0 mmol/L | < 7.8 mmol/L | < 5.7% |
| Prediabetes | 6.0 – 6.9 mmol/L | 7.8 – 11.0 mmol/L | 5.7 – 6.4% |
| Diabetes | ≥ 7.0 mmol/L | ≥ 11.1 mmol/L | ≥ 6.5% |
Reference ranges based on Australian Diabetes Society guidelines. HbA1c reflects average blood glucose over approximately 3 months.
Why Early Detection Matters
Prediabetes is not inevitable diabetes — it is a reversible condition. People who are identified at the prediabetes stage and who make meaningful changes to their weight, diet, and activity levels can prevent or delay the onset of Type 2 Diabetes, sometimes indefinitely. The earlier the detection, the greater the opportunity for intervention.
At MedSurg Weight Loss, metabolic assessment — including screening for diabetes and prediabetes — is a routine part of every consultation. We take the time to explain what your blood test results mean and, importantly, to help you act on them. If prediabetes or diabetes is identified, weight loss is one of the most powerful tools available to manage and even reverse the condition. Book an appointment or explore our Medical Weight Loss and Metabolic Health services.
Medical disclaimer: This article is for general educational purposes only. Blood glucose reference ranges may vary slightly between laboratories and guidelines. Please consult your doctor for interpretation of your individual blood test results and personalised management advice.