When you go for a blood test, your doctor will likely check things like cholesterol, blood glucose, HbA1c, and liver health. But did you know there’s a simple blood test that could reveal if you’re heading towards type 2 diabetes—well before other tests raise the alarm?
This overlooked test is called the fasting insulin test. It’s not yet a standard part of most health checks. Dr Peter Brukner, founder of Defeat Diabetes, calls for this to change, believing it’s the one test that could prevent millions from developing type 2 diabetes.
What is insulin and why does it matter?
Insulin is a hormone your body uses to keep blood glucose levels steady. After you eat carbohydrates (like bread, rice or sweets), your body breaks them into glucose (sugar). Insulin helps move that sugar from your blood into your cells to be used for energy.
But here’s the problem: if you eat too many carbs for too long, your cells can stop responding to insulin properly. This is called insulin resistance. Your body reacts by producing even more insulin to keep blood glucose in check. Over time, this can lead to a dangerous cycle: rising insulin levels, weight gain (especially belly fat), and eventually, type 2 diabetes.
The tricky part? You can have high insulin levels for years—without any obvious symptoms.
The test that could detect type 2 diabetes early
Most doctors rely on a blood glucose test to screen for type 2 diabetes. But the damage may have already begun by the time your blood glucose levels are high enough to raise a red flag.
That’s where the fasting insulin test comes in. This test measures how much insulin your body produces while fasting (after not eating for about eight hours). High insulin levels can signal insulin resistance, warning you to make changes before it’s too late.
Dr Brukner’s personal experience
Dr Brukner knows firsthand how important this test can be. At 60, he thought he was in good health, even though he was carrying extra weight. His routine blood tests were normal—except for slightly raised liver markers and triglycerides, which didn’t seem too worrying at the time.
But when he added a fasting insulin test, the results shocked him. His insulin levels were sky-high, a condition called hyperinsulinemia. This was an early warning sign of type 2 diabetes, driven by decades of eating a high carb diet.
Armed with this knowledge, Dr Brukner switched to a low carb diet, which lowered his insulin levels, improved his liver health and helped him lose 13 kg—all in just a few months.
Why isn’t this test common practice?
Despite its importance, the fasting insulin test isn’t part of most routine check-ups. Dr Brukner believes this is due to a lack of awareness about insulin’s role in health. Some doctors may also worry that insulin levels can vary slightly from day to day. However, for Dr Brukner, the potential benefits far outweigh these concerns.
What are healthy insulin levels?
While labs often list a “normal” range of 5-20 mIU/L, experts including Dr Brukner recommend aiming for less than 8 mIU/L, with under 5 mIU/L being ideal.
Manage your health
If you’re over 50, have a family history of diabetes, or carry extra weight, it’s worth asking your doctor about a fasting insulin test. Detecting insulin resistance early could give you the chance to make lifestyle changes—like cutting back on carbs—that can prevent type 2 diabetes altogether.
Final thoughts
Type 2 diabetes affects nearly 2 million Australians and develops over years, not overnight. With simple tools like the fasting insulin test, we can detect early warning signs and take action before the disease takes hold.
Ask your doctor about adding a fasting insulin test to your next health check. It could be the test that changes everything.
