Insulin Resistance and Prediabetes: The Numbers, and What Reverses Them
Metabolic health · Blood sugar
Blood sugar is usually the last thing to change. Catching the problem early is the whole point, because this stage is very reversible.
Written for my patients. If you are not one, read "call me" as "call your own clinician", and take the questions here to them.
What insulin resistance is
Insulin is the hormone that moves sugar out of your blood and into your cells. When cells stop responding well, your pancreas makes more insulin to compensate. For years, often a decade or more, that extra insulin keeps your blood sugar looking normal. Eventually the pancreas cannot keep up, and blood sugar starts to rise. That is prediabetes, and after that, type 2 diabetes.
Clues that insulin resistance may be building: weight gained around the middle, high triglycerides with low HDL, dark velvety skin on the neck or underarms, fatty liver, PCOS, or high blood pressure.
The numbers
| Test | What the result means |
|---|---|
| A1c | Normal under 5.7%. Prediabetes 5.7 to 6.4%. Diabetes 6.5% or higher. |
| Fasting glucose | Normal under 100. Prediabetes 100 to 125. Diabetes 126 or higher. |
| 2-hour glucose test | Normal under 140. Prediabetes 140 to 199. Diabetes 200 or higher. |
| Fasting insulin | No official cutoff, and labs measure it differently. It can show insulin resistance years before glucose moves, so I use it as an early clue and track your trend. |
How much each approach cut the risk of diabetes over about 3 years
| Approach | Risk reduction |
|---|---|
| Metformin | 31% |
| Lifestyle program | 58% |
More than 3,000 adults with prediabetes. The lifestyle group aimed for 7 percent weight loss and 150 minutes of activity a week. In people over 60, lifestyle cut the risk by 71 percent. The benefit was still there 15 years later. Diabetes Prevention Program, N Engl J Med 2002 · 3,234 adults · randomized.
What moves the needle
Strong evidence
Good supporting evidence
The part people do not hear
How often to recheck
With prediabetes, I recheck A1c at least once a year, and every 3 to 6 months while we are actively working on it. The Endocrine Society also suggests daily vitamin D above the standard amount for adults with high-risk prediabetes; ask me whether that applies to you.
I wrote this for my patients, and it reads the same for everyone: general information, not a plan. If you would like your own numbers read against your own story, that is what a Lab Second Look is for. If you are not sure where to start, the free intro call is fifteen minutes.
A note on how to use this. General information for my patients, not individualized advice.
- American Diabetes Association. Standards of Care in Diabetes—2026. Diabetes Care 2026;49(Suppl 1).
- Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346(6):393–403.
- Buffey AJ et al. The acute effects of interrupting prolonged sitting time in adults with standing and light-intensity walking on biomarkers of cardiometabolic health. Sports Med 2022;52(8):1765–87.
- Demay MB et al. Vitamin D for the prevention of disease: Endocrine Society guideline. J Clin Endocrinol Metab 2024;109(8):1907–47.
Trang Ca Laube, FNP-BC, FMACP · Reclaim Power Telehealth · Updated September 2026
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