Prediabetes

Prediabetes means blood glucose is higher than normal but below the threshold for type 2 diabetes. It's a warning stage rather than a disease — and it's the most useful point at which to intervene, because it's frequently reversible.

What it means

Two forms exist, and it's possible to have either or both:

• Impaired fasting glucose — glucose is raised after fasting
• Impaired glucose tolerance — glucose stays raised after a glucose load

They reflect slightly different aspects of glucose handling. Both indicate that insulin resistance has progressed far enough that compensation is faltering.

Verify and insert: current Australian diagnostic thresholds for both, plus the HbA1c range used to indicate prediabetes.

What it predicts

Without intervention, a substantial proportion of people with prediabetes progress to type 2 diabetes over subsequent years — though progression is not inevitable, and a meaningful proportion return to normal glucose regulation.

Less well known: prediabetes already carries elevated cardiovascular risk, and is associated with liver fat and the other components of metabolic syndrome. It isn't a benign holding state.

Verify: current progression-rate figures. Cite an Australian source.

Why it's usually missed

It causes no symptoms. Most diagnoses are incidental — found on a routine test, during a health check, or while investigating something else.

This is the argument for risk assessment rather than waiting for symptoms. If you have several risk factors, ask your GP about testing; the tools involved are cheap and widely available.

What helps

Prediabetes responds better to intervention than any later stage.

Weight loss of a modest percentage substantially reduces progression risk. Physical activity improves insulin sensitivity independently of weight change — both aerobic and resistance training contribute. Dietary pattern — reducing refined carbohydrates, added sugars and ultra-processed foods; Mediterranean-style patterns have the strongest evidence. Sleep and alcohol — untreated sleep apnoea worsens insulin resistance; alcohol contributes calories and liver fat. Medication is considered in some cases, at clinical discretion.

Monitoring matters too. A prediabetes result should be followed by a plan and a recheck interval, not filed away. If neither was discussed, ask.

Tools: Type 2 diabetes risk check Next: Insulin resistance · Type 2 diabetes explained · Find a GP →