Lifestyle Change for Prediabetes: NHS Guide

Lifestyle change for prediabetes is the most effective and evidence-based way to prevent or delay the progression to type 2 diabetes. In the UK, prediabetes is clinically referred to as non-diabetic hyperglycaemia (NDH), and around 13.6 million people in England are estimated to be at increased risk of developing type 2 diabetes. The encouraging reality is that targeted changes to diet, physical activity and weight can restore normal blood glucose levels in many people. This article explains what those changes involve, how much difference they make, and what the NHS recommends for people who have received an NDH result.

What is prediabetes and why does it matter?

Prediabetes, or non-diabetic hyperglycaemia, is identified by an HbA1c of 42 to 47 mmol/mol and significantly raises the risk of type 2 diabetes, though targeted lifestyle changes can restore normal glucose regulation in many people.

Prediabetes, also referred to in UK clinical settings as non-diabetic hyperglycaemia (NDH) or being at high risk of type 2 diabetes, is a condition in which blood glucose levels are higher than normal but not yet high enough to meet the diagnostic threshold for type 2 diabetes. It matters because it significantly raises the risk of progressing to type 2 diabetes if left unaddressed.

In the UK, NDH is typically identified through an HbA1c reading of 42 to 47 mmol/mol.^[1][2] Fasting plasma glucose thresholds vary by context: the World Health Organisation defines impaired fasting glucose as 6.1 to 6.9 mmol/L, while NHS Diabetes Prevention Programme (NHS DPP) eligibility uses a broader fasting glucose range of 5.5 to 6.9 mmol/L for people identified as high risk. If you have received a result in either range, your GP or practice nurse can advise which applies to you. Diabetes UK estimates that around 13.6 million people in England are at increased risk of developing type 2 diabetes.

The condition develops when the body becomes less efficient at using insulin, a process known as insulin resistance. Over time, the pancreas struggles to produce enough insulin to keep blood glucose within a healthy range. Without intervention, a proportion of people with NDH will develop type 2 diabetes, bringing with it an increased risk of cardiovascular disease, kidney disease, nerve damage and sight problems.

It is worth noting that HbA1c is not suitable for everyone. It is not recommended during pregnancy, in children, or in people with certain haemoglobinopathies or anaemias, where it may give an unreliable result.^[23] In these situations, a fasting plasma glucose or oral glucose tolerance test (OGTT) may be used instead. Your GP can advise on the most appropriate test for your circumstances.

The encouraging news is that NDH is not an inevitable step towards type 2 diabetes. Because blood glucose levels are still in a potentially reversible range, targeted lifestyle changes can restore normal glucose regulation in many people. Early identification through NHS Health Checks or routine blood tests is therefore important, as it opens a window for intervention before the condition progresses further. The NHS Health Check, available to adults aged 40 to 74 in England who are not already diagnosed with a relevant condition, includes a cardiovascular risk assessment; blood glucose testing is then arranged where clinically indicated based on that assessment.^[5][6]

Which lifestyle changes make the biggest difference?

The combination of dietary improvement, at least 150 minutes of moderate aerobic activity per week and modest weight loss produces the greatest reduction in progression risk, outperforming any single measure alone.

The lifestyle changes that make the biggest difference in prediabetes are a combination of dietary improvement, regular physical activity and, where relevant, modest weight loss. Evidence consistently shows that these three elements together are more effective than any single measure alone. Large-scale trials, including the US Diabetes Prevention Program (Knowler et al., New England Journal of Medicine, 2002) and the Finnish Diabetes Prevention Study (Tuomilehto et al., New England Journal of Medicine, 2001), demonstrated that structured lifestyle programmes reduced progression to type 2 diabetes by around 58% compared with control groups.

In terms of diet, the most evidence-based approach involves:

• Reducing refined carbohydrates and added sugars, which cause rapid rises in blood glucose

• Increasing dietary fibre through vegetables, pulses, wholegrains and fruit, which slows glucose absorption

• Limiting saturated fat, particularly from processed foods and red meat

• Controlling portion sizes to avoid large post-meal glucose spikes, with a focus on overall carbohydrate quality and total energy intake rather than meal frequency alone

The NHS Eatwell Guide provides a practical framework for achieving a balanced diet in line with these principles and is a useful starting point for anyone looking to improve their eating habits.

Physical activity is equally important. The UK Chief Medical Officers' Physical Activity Guidelines recommend at least 150 minutes of moderate-intensity aerobic activity per week, such as brisk walking, cycling or swimming, alongside muscle-strengthening activities on two or more days.^[7][8] Exercise improves insulin sensitivity directly, meaning the body uses glucose more efficiently even before significant weight loss occurs.

Stopping smoking is strongly recommended; free support is available through NHS Stop Smoking Services. Reducing alcohol intake also supports better glucose regulation and reduces cardiovascular risk, which is already elevated in people with prediabetes. The UK Chief Medical Officers advise keeping alcohol consumption to no more than 14 units per week, spread over three or more days, with several alcohol-free days each week.^[9][10]

Sleep quality and stress management are increasingly recognised as contributing factors, as poor sleep and chronic stress can raise cortisol levels, which in turn may impair insulin sensitivity, though the evidence base in this area continues to develop.

Bolt Pharmacy is a GPhC-registered UK online pharmacy (regulated by the General Pharmaceutical Council in Great Britain) offering online weight-management consultations, with prescriber review and pharmacist support, which may be relevant for those whose prediabetes is linked to excess weight.

How much weight do I need to lose to reverse prediabetes?

Losing 5 to 10% of body weight is associated with a clinically meaningful reduction in progression risk, with greater losses of 10 to 15% producing more substantial and sustained improvements in glucose regulation.

Losing 5 to 10% of body weight is associated with a clinically meaningful reduction in the risk of progressing from prediabetes to type 2 diabetes, and for some people, even modest losses within this range are sufficient to return blood glucose to a normal level. For a person weighing 90 kg, this equates to approximately 4.5 to 9 kg. Greater weight loss, particularly in the range of 10 to 15%, is associated with more substantial and sustained improvements in glucose regulation, as shown in secondary analyses from the Diabetes Prevention Program and related studies.

Weight loss improves prediabetes through several mechanisms. Reducing excess body fat, particularly visceral fat stored around the abdomen and liver, directly reduces insulin resistance. As the liver and muscle cells become more responsive to insulin, the pancreas no longer needs to work as hard to maintain normal blood glucose levels. This can allow HbA1c to fall back into the normal range.

Waist circumference is also a useful indicator of metabolic risk. NICE and WHO guidance identifies raised waist circumference (above 94 cm in men and above 80 cm in women of most ethnic backgrounds) as a marker of increased cardiovascular and metabolic risk.^[3] For people of South Asian, Chinese, Japanese and some other ethnic backgrounds, lower BMI thresholds apply in UK risk assessment: a BMI of 23 kg/m2 or above is used to indicate increased risk, compared with 25 kg/m2 in the general population. If you are unsure which threshold applies to you, your GP can advise.

It is important to note that weight loss alone is not the only route to improvement. People who are already within a healthy weight range can still have prediabetes, and for them, dietary quality and physical activity are the primary levers. The method of weight loss also matters: very low-calorie diets without professional supervision can be difficult to sustain and may not produce lasting metabolic benefit. Clinician-supervised low-calorie or very low-calorie approaches may be appropriate in some circumstances, as outlined in NICE obesity management guidance, but should only be undertaken with professional support. A gradual, sustainable reduction of around 0.5 to 1 kg per week, achieved through dietary change and increased activity, is the approach recommended by NHS guidance as the most effective long-term strategy.

What does the NHS recommend for prediabetes prevention?

The NHS recommends referral to the Healthier You NHS Diabetes Prevention Programme, a free nine-month structured intervention covering diet, physical activity and weight management, with annual HbA1c monitoring.

The NHS recommends that people identified with non-diabetic hyperglycaemia (NDH) are referred to the NHS Diabetes Prevention Programme (NHS DPP), known as Healthier You. This is a structured, evidence-based behavioural intervention delivered in group or digital formats across England. The programme is free at the point of use and provides personalised support on diet, physical activity and weight management over approximately nine months. Referral is typically made by a GP or practice nurse following a blood test result indicating NDH.

NICE guidance (PH38, which covers the identification and prevention of type 2 diabetes in adults at high risk) supports the use of intensive lifestyle interventions for people at high risk of type 2 diabetes, recommending that these programmes address diet, physical activity and, where appropriate, weight management in a structured and sustained way. NICE does not recommend routine pharmacological treatment for NDH in the absence of other clinical indications, meaning lifestyle change remains the primary recommended approach.

The NHS Health Check programme, available to adults aged 40 to 74 in England who are not already diagnosed with a relevant condition, includes a cardiovascular risk assessment.^[5][6] Blood glucose testing (HbA1c or fasting plasma glucose) is then arranged where clinically indicated based on that assessment, and can identify NDH before symptoms develop. Similar prevention programmes exist in Scotland, Wales and Northern Ireland, though the specific referral pathways and programme names differ; your GP or local health board can advise on what is available in your area.

People who receive an NDH result are encouraged to:

• Attend their NHS DPP referral if offered one

• Discuss their results with their GP, particularly if they have other risk factors such as a family history of type 2 diabetes, high blood pressure or a BMI above the relevant threshold for their ethnic background

• Have their HbA1c rechecked at least annually to monitor whether levels are improving, stable or rising, in line with NICE and NHS clinical guidance on monitoring people with NDH

Can diet and exercise really stop prediabetes turning into type 2 diabetes?

Yes; the US Diabetes Prevention Program found lifestyle intervention reduced type 2 diabetes incidence by 58%, outperforming metformin, with protective effects persisting for many years after the programme ended.

Yes, diet and exercise can genuinely prevent or substantially delay the progression of prediabetes to type 2 diabetes, and this is one of the most robustly evidenced findings in preventive medicine. The US Diabetes Prevention Program (Knowler et al., New England Journal of Medicine, 2002), which followed over 3,000 participants, found that lifestyle intervention reduced the incidence of type 2 diabetes by approximately 58% over nearly three years, outperforming metformin, which reduced incidence by 31% in the same trial.^[11] Long-term follow-up data from the Diabetes Prevention Program Outcomes Study (DPPOS) show that the protective effect of lifestyle intervention persists for many years, even after the formal programme ends.^[14] The Finnish Diabetes Prevention Study produced comparable findings.

The biological explanation is well understood. Sustained dietary improvement and regular physical activity reduce visceral fat, lower circulating insulin levels, improve the sensitivity of muscle and liver cells to insulin, and reduce low-grade systemic inflammation, all of which are drivers of progression from prediabetes to type 2 diabetes. These changes are measurable within weeks of starting a consistent programme.

It is also worth noting that some people with prediabetes do not progress to type 2 diabetes even without intervention, and a proportion return to normal glucose levels spontaneously. However, relying on spontaneous resolution is not a clinically sound strategy, particularly for those with additional risk factors. The evidence strongly supports active engagement with lifestyle change rather than a watchful waiting approach. NHS England evaluations of the Healthier You NHS DPP have shown that structured programme support produces better outcomes than general advice alone, with participants achieving meaningful reductions in weight and improvements in glucose levels.^[18][19]

How long does it take to see results from lifestyle changes?

Fasting blood glucose can improve within weeks of consistent lifestyle change; HbA1c, reflecting a three-month average, is typically reassessed at three to six months, with some people returning to the normal range within this period.

Measurable improvements in blood glucose can begin to appear within a few weeks of consistent lifestyle change, though the timeline varies depending on the individual's starting point, the degree of change made and other health factors. Fasting blood glucose tends to respond relatively quickly to dietary modification, while HbA1c, which reflects average blood glucose over approximately three months, takes longer to show a meaningful shift. In line with NICE and NHS clinical guidance on monitoring people with NDH, HbA1c is typically reassessed at around three to six months after starting a lifestyle programme, and then at least annually thereafter.

Physical activity can improve insulin sensitivity within days of starting a regular routine, even before significant weight loss has occurred. This is because muscle contraction during exercise activates glucose uptake independently of insulin, providing an immediate metabolic benefit.^[15][16] Over weeks and months, as fitness improves and body composition changes, these effects become more sustained.

For most people, a realistic expectation is that a sustained programme of dietary improvement and regular activity over three to six months will produce a noticeable reduction in HbA1c, with some individuals returning to the normal range within this period. Factors that influence the speed of response include:

• Starting HbA1c level: those closer to the lower end of the prediabetes range tend to respond more quickly

• Degree of weight loss achieved, particularly reduction in abdominal fat

• Consistency of activity, with regular moderate exercise producing better results than occasional intense sessions

• Dietary adherence, particularly reduction in refined carbohydrates and added sugars

If you develop symptoms that may suggest blood glucose is rising significantly, such as increased thirst, passing urine more frequently than usual, unexplained weight loss or blurred vision, you should seek prompt medical review rather than waiting for a scheduled blood test. If you are pregnant or planning a pregnancy, or if you start a medication that can affect blood glucose (such as corticosteroids), speak to your GP promptly, as more frequent monitoring and different testing methods may be needed. HbA1c is not recommended for monitoring during pregnancy; fasting plasma glucose or an oral glucose tolerance test is used instead.

If blood glucose levels have not improved after six months of genuine lifestyle change, a GP should be consulted to review the approach and consider whether additional support or investigation is needed.

Scientific References

1. Type 2 diabetes: prevention in people at high risk (PH38) – recommendations.
2. Type 2 diabetes: prevention in people at high risk (PH38) – guideline overview.
3. Full guideline, section 2 – Identification and classification (NG246 evidence).
4. Appendix A1: Summary of evidence from surveillance (NG246) – BMI thresholds for South Asian and other ethnic groups.
5. NHS Health Check.
6. NHS Health Checks: applying All Our Health.
7. UK Chief Medical Officers' physical activity guidelines.
8. Physical activity guidelines for adults aged 19 to 64.
9. Alcohol consumption: advice on low risk drinking – UK Chief Medical Officers' guidelines.
10. Drink less alcohol – Better Health.
11. Knowler WC et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002..
12. Tuomilehto J et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med. 2001..
13. Lindström J et al. The Finnish Diabetes Prevention Study (DPS). 2003..
14. Diabetes Prevention Program Research Group. Long-term effects of lifestyle intervention or metformin on diabetes development and microvascular complications. Lancet Diabetes Endocrinol. 2015..
15. Richter EA, Hargreaves M. Exercise, GLUT4, and skeletal muscle glucose uptake. 2013..
16. Kristiansen S et al. Skeletal muscle pathways of contraction-enhanced glucose uptake. Int J Sports Med. 2008..
17. Rose AJ, Richter EA. Exercise signalling to glucose transport in skeletal muscle. Proc Nutr Soc. 2005..
18. McManus E et al. Population level impact of the NHS Diabetes Prevention Programme. Lancet Reg Health Eur. 2022..
19. Valabhji J et al. Early outcomes from the English National Health Service Diabetes Prevention Programme. Diabetes Care. 2020..
20. Finlay A et al. 'Finishing the race' – a cohort study of weight and blood glucose change among the first 36,000 patients in a large-scale diabetes prevention programme. Int J Behav Nutr Phys Act. 2022..
21. Diabetes profile: statistical commentary, March 2025.
22. Vaccaro O et al. Changing the definition of impaired fasting glucose. 2005..
23. NICE. Diabetes in pregnancy: management from preconception to the postnatal period (NG3)..

Frequently Asked Questions