Prediabetes: the warning you can act on
Prediabetes means your blood glucose is higher than normal but not yet in the diabetes range: an HbA1c of 5.7–6.4%, a fasting glucose of 100–125 mg/dL, or a two-hour value of 140–199 mg/dL after a glucose drink. It usually causes no symptoms at all, which is why it is found on a routine test. It matters because it is the stage at which the process is still reversible — losing 5–7% of body weight and walking 150 minutes a week reduces progression to type 2 diabetes by around 58%, which is better than any tablet has achieved in the same trials.
Diabetologist & General Physician · MBBS
Prediabetes is not a mild form of diabetes. It is the stage before it, and the reason to name it at all is that this is the point where the trajectory can still be changed — often without medication.
The numbers
| Test | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| HbA1c | Below 5.7% | 5.7 – 6.4% | 6.5% or above |
| Fasting glucose | Below 100 mg/dL | 100 – 125 mg/dL | 126 mg/dL or above |
| 2-hour OGTT | Below 140 mg/dL | 140 – 199 mg/dL | 200 mg/dL or above |
It usually has no symptoms
Most people with prediabetes feel entirely well. That is the difficulty: nothing prompts you to be tested. A minority notice the classic early signs — passing more urine, being unusually thirsty, tiredness, or slow-healing cuts — but by then the numbers are often already in the diabetes range.
One visible sign is worth knowing: dark, velvety thickening of the skin at the back of the neck, the armpits or the groin. This is acanthosis nigricans, and it is a marker of insulin resistance rather than dirt — it cannot be scrubbed off, and people often try.
Who should be tested
What actually works
The Diabetes Prevention Program remains the clearest evidence we have. Participants who lost 5–7% of their body weight and did 150 minutes a week of moderate activity cut their progression to type 2 diabetes by about 58% over three years. Metformin reduced it by about 31% in the same trial — useful, but less than the lifestyle arm.
- Lose 5–7% of your weight. For an 80 kg person that is 4–6 kg, not 20. This is the single most effective step.
- Walk 150 minutes a week. Thirty minutes, five days. It does not have to be continuous, and brisk walking counts.
- Cut sugary drinks entirely. Soft drinks, packaged juice and sweetened tea deliver glucose faster than almost anything else in the diet.
- Change the shape of the plate rather than counting calories — see the diabetes eating guide for how this works with roti, rice and salan.
- Add resistance work twice a week. Muscle is where most glucose is disposed of, so building it improves insulin sensitivity directly.
- Sleep and stress matter. Short sleep and chronic stress both raise glucose through cortisol.
Should you take metformin?
Sometimes. Guidelines suggest considering metformin in prediabetes for those at highest risk: BMI over 35, age under 60, a history of gestational diabetes, or rising HbA1c despite lifestyle change. It is not a substitute for the lifestyle work, and it is a decision to make with your doctor rather than a default.
How often to re-check
Once a year for most people with prediabetes, or every six months if your HbA1c is at the upper end or rising. Re-testing is how you find out whether what you changed is working — and finding that it is, is usually what keeps people going.
Common questions
Still not sure what to do?
Reading about a symptom only goes so far. A doctor who can ask you questions and examine you will get further in ten minutes than any article can.
