Prediabetes: What It Means and What to Do Next

Heart & Metabolic Health

Prediabetes is one of those results that can sound more frightening than it needs to be.

It does not mean you have diabetes. It means your blood glucose is above the healthy range, but not high enough to diagnose diabetes.

I prefer to think of prediabetes as an early warning rather than a diagnosis of inevitable disease.

It is a chance to act while there is still a great deal you can influence.

What is prediabetes?

When you eat carbohydrate, your body breaks much of it down into glucose. Insulin helps move glucose from your bloodstream into your cells, where it can be used for energy.

Over time, some people become less sensitive to insulin. The pancreas compensates by producing more, but eventually blood glucose can begin to rise.

Prediabetes is an umbrella term often used when glucose results are above the healthy range but below the level used to diagnose diabetes.

Your GP may describe the result more specifically as impaired fasting glucose or impaired glucose tolerance, depending on the test used.

• a fasting blood glucose test
• an HbA1c blood test
• an oral glucose tolerance test

An HbA1c of 6.0-6.4% (42-46 mmol/mol) is commonly considered an increased-risk range. Impaired fasting glucose generally refers to a fasting glucose of 6.1-6.9 mmol/L.

These measurements are related, but they are not interchangeable. Your GP will interpret the result according to which test was performed and your individual circumstances.

What does HbA1c actually tell us?

HbA1c gives an indication of your average blood glucose over roughly the previous two to three months.

It is useful because you do not need to be fasting and it tells us more than a single glucose reading.

But it is not a perfect test.

Anaemia, some haemoglobin disorders, pregnancy, kidney disease and other conditions can affect its reliability. Sometimes a fasting glucose or glucose tolerance test provides useful additional information.

This is why I interpret the person as well as the number.

An HbA1c just above the healthy range in an otherwise healthy person may lead to a different discussion from the same result in someone with increasing weight, high blood pressure, abnormal cholesterol, previous gestational diabetes or a strong family history.

Does prediabetes mean I will get diabetes?

No.

But it should not simply be ignored.

Prediabetes increases your future risk of type 2 diabetes. It also often occurs alongside other cardiovascular risk factors, such as excess weight, high blood pressure and abnormal cholesterol.

The encouraging part is that progression is not inevitable.

Improving physical activity, diet and weight where appropriate can substantially reduce the risk of developing type 2 diabetes.

So I don’t regard prediabetes as something to panic about. I do regard it as something worth acting on.

Why did I develop it?

Usually there isn’t one cause.

Risk tends to increase with a combination of factors such as:

• excess weight, particularly around the abdomen
• increasing age
• family history of type 2 diabetes
• low physical activity
• previous gestational diabetes
• polycystic ovary syndrome
• high blood pressure or abnormal cholesterol
• some medicines
• particular ethnic backgrounds

Genetics matters. So do age and circumstances.

This is important because prediabetes should not become a judgement about someone’s lifestyle.

Two people can eat similarly, exercise similarly and have very different metabolic risks.

The useful question is not “Whose fault is this?” It is: “What can we change from here?”

How much difference does weight loss make?

If you are carrying excess weight, even modest weight loss can improve insulin sensitivity and blood glucose.

Australian guidance for people at increased diabetes risk supports structured lifestyle changes incorporating regular physical activity and, where appropriate, weight reduction. Losing around 5-10% of body weight can produce meaningful metabolic benefits for many people carrying excess weight.

You do not need to reach an “ideal” BMI before there is a benefit.

And weight is not the only target.

Waist circumference, fitness, blood pressure, cholesterol, diet quality, sleep and smoking all contribute to long-term health.

What should I eat?

There is not one compulsory “prediabetes diet”.

I generally prefer sustainable eating patterns over highly restrictive diets that are difficult to maintain.

A useful starting point is to build most meals around foods such as:

• vegetables
• adequate protein
• legumes and other high-fibre foods
• wholegrains where appropriate
• nuts and seeds
• whole fruit
• healthier unsaturated fats

Reducing highly processed foods, excess kilojoules and sugary drinks can also help.

The exact approach should fit your weight goals, preferences, culture, medical conditions and what you can realistically sustain.

A diet that looks perfect on paper but lasts three weeks isn’t particularly useful.

What about carbohydrates?

Having prediabetes does not mean carbohydrates are forbidden.

The type, quantity and context matter.

A large soft drink and a serving of lentils both contain carbohydrate, but they have very different nutritional effects.

Wholegrains, legumes, vegetables and whole fruit provide fibre and other nutrients and can form part of a healthy diet.

For some people, reducing refined carbohydrate is useful. For others, the bigger issue may be portion size, snacking, alcohol, sugary drinks or overall energy intake.

The best dietary change is the one that addresses your actual problem.

Exercise does more than burn calories

Muscle is an important site for glucose disposal.

Regular physical activity can improve your body’s sensitivity to insulin. It also benefits fitness, blood pressure, weight, sleep and cardiovascular health.

A sensible target for many adults is at least 150 minutes of moderate-intensity physical activity each week, ideally combined with resistance or strength exercise.

But don’t let the target stop you from starting.

If you currently do very little, going from zero to three walks each week is progress. Build from there.

Do I need medication?

Usually, lifestyle measures are the starting point.

Medication may sometimes be considered for people at particularly high risk of progressing to diabetes, but it is not automatically required because an HbA1c has entered the prediabetes range.

For some people, treating obesity itself, including with medication where appropriate, may form part of reducing overall metabolic risk.

That decision should be based on your overall health, weight-related risks, likely benefits, possible side effects, preferences and cost – not simply on one prediabetes blood result.

Do I need to check my glucose at home?

Usually not.

Most people with uncomplicated prediabetes do not need to prick their finger several times a day or wear a continuous glucose monitor.

For most patients, periodic laboratory testing combined with attention to the underlying risk factors tells us what we need to know.

Routine insulin-level testing is also generally not useful for assessing insulin resistance in this setting.

More data isn’t automatically better healthcare.

What else should my GP check?

Prediabetes is often part of a broader metabolic picture.

When I see it, I am usually interested in more than glucose alone.

Depending on the person, it may be worth reviewing:

• weight and waist circumference
• blood pressure
• cholesterol and triglycerides
• smoking
• alcohol
• physical activity and diet
• overall cardiovascular risk
• family history
• medicines
• liver health
• sleep, including possible sleep apnoea

The aim is not simply to stop one laboratory number crossing into the diabetes range.

It is to reduce your overall future health risk.

How often should it be checked?

People with impaired glucose regulation will usually need ongoing testing. Australian guidance generally recommends at least annual glucose testing for people with impaired fasting glucose or impaired glucose tolerance.

The timing may be different depending on your original result and overall risk.

I may suggest checking sooner if the result is approaching the diabetes range, symptoms develop, weight is changing significantly or there are other reasons for concern.

Trends are often more useful than isolated numbers.

What symptoms should I watch for?

Prediabetes itself usually causes no symptoms.

If glucose rises substantially into the diabetes range, symptoms can include:

• unusual thirst
• passing urine more frequently
• unexplained weight loss
• marked fatigue
• blurred vision
• recurrent infections

If these occur, don’t simply wait for your next routine blood test.

Arrange medical review.

Can I reverse prediabetes?

Sometimes blood glucose returns to the healthy range, particularly after meaningful changes in weight, diet and physical activity.

That’s excellent.

But I prefer not to think of it as receiving a permanent all-clear.

The underlying tendency may remain, particularly where age, genetics or previous metabolic problems contribute.

If your numbers improve, the habits that helped them improve are generally worth continuing.

Start with one action

If you have just been told you have prediabetes, don’t try to redesign your entire life this weekend.

Choose one meaningful change you can sustain.

That might be:

• walking for 30 minutes on most days
• replacing sugary drinks with water
• improving your usual breakfast or lunch
• adding resistance training twice a week
• reducing alcohol
• reducing frequent takeaway meals
• beginning gradual weight loss if excess weight is contributing

Then build from there.

Consistency usually matters more than a perfect two-week health kick.

What should I bring to my next appointment?

If you’ve been told you have prediabetes, it can help to bring:

• recent blood results if they were done elsewhere
• an up-to-date medication list
• relevant family history of diabetes or heart disease
• your weight history if you know it
• an idea of what you normally eat and drink
• an honest estimate of your usual physical activity

You don’t need to arrive with a perfect diet plan.

We need to identify the one or two changes most likely to make a difference for you.

The Bottom Line

Prediabetes is not diabetes, and diabetes is not inevitable.

It is an early sign that your body is having more difficulty managing glucose and that your future metabolic and cardiovascular risk deserves attention.

The most useful response is usually not fear, supplements or obsessive glucose monitoring.

It is a practical plan: improve diet quality, move more, address excess weight where relevant, manage the rest of your cardiovascular risk and repeat the right tests at the right time.

If you’ve just discovered you have prediabetes, start with one achievable change and discuss the bigger picture with your GP.

Early action can make a meaningful difference.

Related Q Guides

• Preventing Type 2 Diabetes
• Maintaining a Healthy Weight
• Healthy Diet
• Exercise
• Understanding Blood Pressure
• Cholesterol and Heart Risk