Prediabetes usually has no symptoms at all, so the only reliable sign is a blood test result just above normal: an HbA1c of 5.7% to 6.4% or a fasting glucose of 100 to 125 mg/dL (5.6 to 6.9 mmol/L) under US criteria. The good news is that for many people it can be pushed back into the normal range by losing about 5% to 7% of body weight and building up to 150 minutes of brisk activity a week.
What does prediabetes mean?
Prediabetes means your blood sugar is higher than normal but not yet high enough to be called type 2 diabetes. Your body still makes insulin, but your cells have started to respond to it less well (insulin resistance), so glucose hangs around in the blood longer than it should.
It’s very common. The US Centers for Disease Control and Prevention (CDC) says more than 2 in 5 American adults have it. In India, the national ICMR-INDIAB study in The Lancet Diabetes & Endocrinology found prediabetes in 15.3% of adults, more than the 11.4% who already had diabetes. In the UK, the NHS calls it pre-diabetes or “non-diabetic hyperglycaemia”.
Does prediabetes have any signs or symptoms?
Mostly, no. The US National Institute of Diabetes and Digestive and Kidney Diseases says people with insulin resistance and prediabetes usually have no symptoms. Cleveland Clinic notes that more than 8 in 10 people with prediabetes don’t know they have it.
There is one physical clue worth knowing about:
- Darkened, velvety skin in the armpits or on the back and sides of the neck. Doctors call this acanthosis nigricans, and Cleveland Clinic lists it as a possible sign of prediabetes. It’s a reason to get tested, not a diagnosis.
If you have been feeling very thirsty, passing urine a lot, losing weight without trying or getting blurred vision, that points more towards diabetes itself than prediabetes. Don’t wait for a routine check in that case; book a blood test soon.
Because the condition is so quiet, risk factors are the better guide. The CDC lists these:
- Being overweight
- Being 45 or older
- A parent, brother or sister with type 2 diabetes
- Being physically active fewer than 3 times a week
- Having had gestational diabetes, or a baby who weighed over 9 lb (about 4 kg)
- Polycystic ovary syndrome (PCOS)
- Being of South Asian, Black, Hispanic/Latino, American Indian, Alaska Native or Pacific Islander background
What blood test numbers mean prediabetes?
This is where a lot of confusion comes from, because the US and UK draw the line in slightly different places. Here’s how the numbers compare.
| Test | Normal | Prediabetes (US, ADA) | Prediabetes (UK, NICE/NHS) | Diabetes range |
|---|---|---|---|---|
| HbA1c | Below 5.7% (below 39 mmol/mol) | 5.7% to 6.4% (39 to 47 mmol/mol) | 42 to 47 mmol/mol (6.0% to 6.4%) | 6.5% (48 mmol/mol) or higher |
| Fasting plasma glucose | Below 100 mg/dL (5.6 mmol/L) | 100 to 125 mg/dL (5.6 to 6.9 mmol/L) | 5.5 to 6.9 mmol/L (99 to 125 mg/dL) | 126 mg/dL (7.0 mmol/L) or higher |
| 2-hour oral glucose tolerance test | Below 140 mg/dL (7.8 mmol/L) | 140 to 199 mg/dL (7.8 to 11.0 mmol/L) | Used less often in UK primary care | 200 mg/dL (11.1 mmol/L) or higher |
The US ranges come from the American Diabetes Association. The UK ranges come from NICE, which defines non-diabetic hyperglycaemia as an HbA1c of 42 to 47 mmol/mol or a fasting glucose of 5.5 to 6.9 mmol/L. India’s large surveys use World Health Organization criteria, which also differ slightly. So an HbA1c of 5.8% would be labelled prediabetes in a US clinic but might be read as “normal, keep an eye on it” in the UK.
The ADA also says a result usually needs repeating on a second day before a diagnosis is confirmed. If you want to understand why your HbA1c and fasting sugar sometimes disagree, see our guide to HbA1c vs fasting blood sugar.
Who should get tested, and how often?
The US Preventive Services Task Force recommends screening adults aged 35 to 70 who are overweight or obese. It suggests starting earlier for groups with higher rates of diabetes, and using a lower BMI cut-off of 23 (rather than 25) for Asian Americans, because many people of Asian background carry more body fat at the same BMI. If your result is normal, repeating it every 3 years is described as reasonable.
In the UK, people found to have non-diabetic hyperglycaemia are advised to have a blood test every year and may be offered a place on the NHS Diabetes Prevention Programme. In India, many people get an HbA1c or fasting sugar through a workplace or lab health package; if you’re of South Asian origin and over 30 with a family history, it’s sensible to ask your doctor whether to check.
Can prediabetes be reversed?
Often, yes, in the sense that your blood sugar can go back into the normal range. It isn’t guaranteed, and it can creep back up if habits slip, so think of it as “back to normal and staying there with effort” rather than a permanent cure.
The best evidence comes from the US Diabetes Prevention Program, a large trial run by the National Institutes of Health (NIDDK). People with prediabetes aimed to lose 7% of their body weight and exercise 150 minutes a week. Over about 3 years:
- The lifestyle group cut their chance of developing type 2 diabetes by 58% compared with placebo.
- In people over 60, the drop was 71%.
- Metformin, a diabetes tablet, cut risk by 31%.
- Fifteen years later, the lifestyle group still had 27% less diabetes than the placebo group.
So lifestyle change did roughly twice as much as the drug, and the benefit lasted.
How to reverse prediabetes: a practical plan
You don’t need a perfect diet. The trial goals were modest, and you can work towards them in steps.
1. Aim to lose 5% to 7% of your weight
For someone weighing 90 kg (198 lb), that’s 4.5 to 6.3 kg (10 to 14 lb). Losing about half a kilo (1 lb) a week is a realistic pace. If you’re not overweight, focus on the activity and food changes below; they still help.
2. Build up to 150 minutes of activity a week
That’s 30 minutes of brisk walking on 5 days, the target the CDC uses. A 10-minute walk after each main meal counts and is easier to stick to than one long session. If you’re starting from zero, our beginner running plan has a walk-run approach you can use later on.
3. Change what’s on your plate
- Swap sugary drinks, sweetened tea and fruit juice for water, plain tea or coffee.
- Fill half your plate with vegetables, a quarter with protein (eggs, fish, chicken, lentils, beans, tofu, paneer) and a quarter with starch.
- Choose higher-fibre starches: oats, barley, whole-wheat roti, brown or parboiled rice, millets, beans.
- Cut down on white bread, pastries, biscuits and fried snacks. Our guide to good carbs vs bad carbs goes through common swaps.
- Don’t skip breakfast and then overeat at night. Regular meal times help many people.
4. Sleep, smoking and stress
NIDDK lists enough sleep and stopping smoking among the changes that lower your risk. If you snore loudly or wake up tired every day, ask your doctor about sleep apnoea.
5. Ask about medicine if you’re at higher risk
Metformin is sometimes offered alongside lifestyle change. US guidance from the USPSTF review notes it worked best in people under 60, with a BMI of 35 or more, with a fasting glucose of 110 mg/dL (6.1 mmol/L) or above, or with a history of gestational diabetes. Your doctor will decide whether it suits you.
A simple 12-week checklist
| When | What to do |
|---|---|
| Week 1 | Note your starting weight and waist size. Replace all sugary drinks. |
| Weeks 2 to 4 | Walk 10 minutes after two meals a day. Add a vegetable to lunch and dinner. |
| Weeks 5 to 8 | Reach 150 minutes of brisk activity a week. Switch to whole grains for most starchy foods. |
| Weeks 9 to 12 | Add two short strength sessions a week (squats, push-ups against a wall, resistance bands). Check your weight is trending down. |
| Month 3 to 6 | Repeat your HbA1c or fasting glucose as your doctor advises. HbA1c reflects roughly the past 2 to 3 months, so testing too soon won’t show the full change. |
When to see a doctor
See a doctor soon (within days, not months) if you have:
- Increased thirst and passing a lot of urine, especially at night
- Weight loss you can’t explain
- Blurred vision
- Cuts or infections that heal slowly, or repeated thrush or urinary infections
- Tingling or numbness in your feet
- A home glucose reading above 200 mg/dL (11.1 mmol/L)
Get emergency help if you have high blood sugar along with vomiting, deep or fast breathing, a fruity smell on your breath, confusion or severe drowsiness. Call your local emergency number (911 in the US, 999 in the UK, 112 in the EU and India).
Also book a check if you’ve had gestational diabetes, have PCOS, or have dark velvety skin patches on your neck or armpits and haven’t had a sugar test in the past year.
Frequently asked questions
How long does it take to reverse prediabetes?
There’s no fixed timeline. Because HbA1c reflects about 2 to 3 months of blood sugar, most people recheck at 3 to 6 months after making changes. Some see their numbers fall into the normal range at that point; others take longer.
Is an HbA1c of 5.7% bad?
In the US it’s the bottom of the prediabetes range. In the UK, the NHS range starts at 42 mmol/mol (6.0%), so 5.7% would usually be watched rather than labelled. Either way, it’s a useful early warning to act on.
Can you have prediabetes if you’re slim?
Yes. Age, family history, PCOS and ethnicity all raise risk regardless of weight, and many people of South Asian background develop raised blood sugar at a lower BMI. That’s why US guidance uses a BMI cut-off of 23 for Asian Americans.
Do I need to give up rice or roti completely?
No. Smaller portions, whole-grain versions and pairing them with vegetables and protein make more difference than cutting out a food group entirely.
Will prediabetes always turn into type 2 diabetes?
No. In the Diabetes Prevention Program, weight loss and regular activity cut the chance of developing type 2 diabetes by more than half over about 3 years.
This article is for general information and is not a substitute for advice from a doctor. If you have symptoms or a health condition, please consult a qualified healthcare professional.
