Clinically reviewed by Associate Professor Christopher O’Donnell, Nurse Practitioner, FACN · Founder and Clinical Director · AHPRA NMW0001453715 · Last reviewed
Insulin resistance means cells respond poorly to insulin, so the pancreas produces more to keep blood glucose normal. It develops years before blood glucose rises, which is why prediabetes is usually silent. Modest weight loss of five to seven percent substantially reduces progression to type 2 diabetes.
What insulin resistance actually is
Insulin moves glucose from the bloodstream into cells. In insulin resistance, cells respond less readily, so the pancreas compensates by producing more insulin to achieve the same effect.
For years this compensation works and blood glucose stays normal. You can have significant insulin resistance with a completely normal fasting glucose, which is why a normal result does not exclude a developing problem. Only when the pancreas can no longer keep pace does glucose begin to rise.
The tests and what they show
Different tests capture different stages.
- Fasting glucose. Normal below 5.6, prediabetes range 5.6 to 6.9, diabetes at 7.0 or above on repeat testing
- HbA1c. Reflects average glucose over roughly three months. Prediabetes range 5.7 to 6.4 percent, diabetes at 6.5 percent or above
- Oral glucose tolerance test. More sensitive, and can detect impaired glucose handling that fasting tests miss
- Fasting insulin. Not routine, but can reveal compensation happening before glucose rises
Signs worth noticing
Insulin resistance is usually silent, but some features suggest it.
- Increasing waist circumference, with fat accumulating centrally
- Acanthosis nigricans, meaning darkened velvety skin in the neck folds, armpits or groin
- Skin tags, particularly around the neck and armpits
- Marked energy dip after carbohydrate heavy meals
- Raised triglycerides with low HDL cholesterol on a lipid profile
- Polycystic ovary syndrome, which is closely associated with insulin resistance
- Fatty liver identified on ultrasound or suggested by raised liver enzymes
The good news about reversibility
Prediabetes is not an inevitable path to diabetes. Large randomised trials, including the Diabetes Prevention Program, found that lifestyle intervention achieving around seven percent weight loss plus 150 minutes of weekly activity reduced progression to type 2 diabetes by roughly fifty eight percent.
Notably, that was more effective than the medication arm of the same trial. The benefit also persisted for years after the intervention period ended.
What helps most
The evidence points to a consistent set of priorities.
- Modest weight loss. Five to seven percent of body weight produces substantial benefit, which is far less than most people assume is required
- Resistance training. Muscle is the largest site of glucose disposal, so building it directly improves glucose handling
- Regular aerobic activity, which improves insulin sensitivity independently of weight change
- Reducing refined carbohydrate and added sugar, particularly sweetened drinks
- Adequate sleep, since even short term restriction measurably reduces insulin sensitivity
- Regular monitoring, so progress and any deterioration are visible early
Frequently asked questions
Can prediabetes be reversed?
Yes. Lifestyle intervention achieving around seven percent weight loss plus regular activity reduced progression to type 2 diabetes by roughly fifty eight percent in large randomised trials.
What HbA1c indicates prediabetes?
An HbA1c between 5.7 and 6.4 percent falls in the prediabetes range. At 6.5 percent or above, diabetes is diagnosed on repeat testing.
Can you have insulin resistance with normal blood glucose?
Yes, and this is common. The pancreas compensates by producing more insulin, keeping glucose normal for years before it begins to rise.
How much weight loss improves insulin resistance?
Five to seven percent of body weight produces substantial improvement, which is considerably less than most people expect to be necessary.
Does exercise help insulin resistance without weight loss?
Yes. Both aerobic and resistance exercise improve insulin sensitivity independently of weight change, partly because muscle is the largest site of glucose disposal.