Prediabetes: the silent warning sign, and how to reverse it
Prediabetes means your blood sugar is higher than it should be, but not high enough to be diabetes. The good news: it can often be reversed.
Medically reviewed by Dr LJ Ncube, MBChB · Updated November 2026
Why it matters
Without changes, many people with prediabetes go on to develop type 2 diabetes within a few years. Prediabetes also raises the risk of heart disease and stroke. Catching it early gives you the best chance to turn it around.
Show as a table
| Lifestyle change | 58% |
| Metformin | 31% |
Source: Knowler WC, et al. N Engl J Med. 2002.
Signs to look out for
Usually there are none. Most people find out from a routine blood test. That's why checks matter if you're at risk.
Who should get checked
- Adults over 35, or younger if you're overweight
- Anyone with a parent, brother or sister with type 2 diabetes
- People with high blood pressure or high cholesterol
- Women who had diabetes in pregnancy, or who have PCOS
- Anyone who isn't very active
The test numbers
| Test | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| HbA1c (average sugar over 3 months) | Below 5.7% | 5.7% to 6.4% | 6.5% or above |
| Fasting blood sugar | Below 5.6 mmol/L | 5.6 to 6.9 mmol/L | 7.0 mmol/L or above |
These are the American Diabetes Association ranges. Some guidelines use slightly different cut-offs, and a single high reading usually needs repeating before a diagnosis.
How to reverse it
In a large study, people with prediabetes who lost about 7% of their body weight and exercised for 150 minutes a week cut their risk of developing diabetes by more than half. Steps that help:
- Lose 5 to 10% of your body weight. For someone weighing 90 kg, that's 4.5 to 9 kg
- Walk briskly, or do another activity, for 30 minutes on 5 days a week
- Cut down on sugary drinks, white bread, white rice and sadza portions
- Fill half your plate with vegetables
- Get your sugar re-checked at least once a year
For some people, a doctor-led weight loss programme, sometimes with medication, makes these changes easier to achieve and keep.
Answer a few questions online and our doctor will reply on WhatsApp, usually within 24 hours.
Common questions
Can prediabetes go away?
Yes, for many people. Losing weight and being more active can bring blood sugar back into the normal range.
Do I need medication for prediabetes?
Usually not. Lifestyle changes come first. Some people at high risk are offered metformin or weight-loss medication.
How often should I be tested?
At least once a year if you have prediabetes, or every 3 years if your result was normal but you're at risk.
Related
Sources
We base our guides on peer-reviewed research and guidance from health authorities. Where studies disagree or evidence is limited, we say so.
- American Diabetes Association. Diagnosis of diabetes and prediabetes. diabetes.org
- Knowler WC, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin (Diabetes Prevention Program). N Engl J Med. 2002. PubMed
This guide is general information, not advice for your situation. Speak to a doctor before starting or changing any medicine.
