How can I reduce my HbA1c? It is one of the most common questions asked by people living with type 2 diabetes or prediabetes in the UK — and the good news is that meaningful improvements are achievable. HbA1c reflects your average blood sugar levels over the past two to three months, and persistently elevated results increase the risk of serious complications including kidney disease, nerve damage, and cardiovascular disease. This article explains what your HbA1c result means, and outlines the evidence-based dietary, lifestyle, and medical strategies recommended by NICE and the NHS to help you lower it safely and effectively.

What Your HbA1c Result Means and Why It Matters

HbA1c reflects average blood glucose over 2–3 months; in the UK, a result of 48 mmol/mol or above on two occasions diagnoses type 2 diabetes, and reducing it lowers the risk of kidney, eye, nerve, and cardiovascular complications.

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HbA1c — or glycated haemoglobin — is a blood test that reflects your average blood sugar (glucose) levels over the preceding two to three months. When glucose circulates in the bloodstream, it attaches to haemoglobin, the protein inside red blood cells. The higher your blood sugar has been over that period, the higher your HbA1c result will be. Because red blood cells live for approximately 120 days, the test provides a reliable snapshot of longer-term glucose control rather than a single moment in time. It is worth noting that HbA1c is weighted towards the most recent weeks, so recent improvements in blood sugar control will have a greater influence on the result than changes made earlier in the period.

In the UK, HbA1c is measured in millimoles per mole (mmol/mol). According to NICE guidelines (NG28):

• Below 42 mmol/mol is considered normal

• 42–47 mmol/mol indicates non-diabetic hyperglycaemia (sometimes called prediabetes)

• 48 mmol/mol or above on two separate occasions is used to diagnose type 2 diabetes in adults without symptoms

For people already living with type 2 diabetes, NICE recommends an individualised target. As a general guide:

• 48 mmol/mol (6.5%) is recommended if blood sugar is managed by lifestyle changes alone or with medicines that do not cause hypoglycaemia (such as metformin)

• 53 mmol/mol (7.0%) is recommended for those taking insulin or sulphonylureas, where the risk of hypoglycaemia is higher

• Targets may be relaxed — for example, to 58 mmol/mol — in older people, those with multiple health conditions, or where tight control poses unacceptable risks

Important limitations of the HbA1c test: HbA1c is not reliable or appropriate in certain situations. It should not be used to diagnose diabetes in pregnancy, in children, or in people with suspected type 1 diabetes or an acute presentation. It may also give misleading results in people with anaemia, haemoglobin variants (such as sickle cell trait or thalassaemia), chronic kidney disease (CKD), or those who have recently had a blood transfusion. In these circumstances, alternative tests such as fasting plasma glucose or an oral glucose tolerance test (OGTT) are used instead. If your HbA1c result does not seem consistent with your day-to-day glucose readings, discuss this with your GP or diabetes team.

Understanding why this number matters is important. Persistently elevated HbA1c is associated with an increased risk of serious long-term complications, including damage to the kidneys (nephropathy), eyes (retinopathy), nerves (neuropathy), and cardiovascular disease. Reducing your HbA1c — even modestly — can meaningfully lower these risks. HbA1c is not fixed; with the right combination of lifestyle changes and, where necessary, medication, most people can achieve meaningful improvements.

Dietary Changes That Can Help Lower HbA1c

Reducing refined carbohydrates and added sugars, increasing dietary fibre, and controlling portion sizes are the most effective dietary strategies; low-carbohydrate diets can also help but require medical supervision if you take insulin, sulphonylureas, or SGLT-2 inhibitors.

Diet is one of the most powerful tools available for reducing HbA1c. Day-to-day glucose patterns can begin to improve relatively quickly with dietary changes, although meaningful reductions in HbA1c are typically seen over 8–12 weeks, reflecting the nature of the test. The fundamental principle is managing the quantity and quality of carbohydrates you consume, since carbohydrates are broken down into glucose and have the most direct effect on blood sugar levels.

Practical dietary strategies supported by evidence include:

• Reducing refined carbohydrates and added sugars — white bread, white rice, sugary drinks, pastries, and processed snacks cause rapid spikes in blood glucose. Replacing these with lower-glycaemic alternatives (such as wholegrain bread, basmati rice, oats, and pulses) produces a slower, more manageable rise in blood sugar.

• Increasing dietary fibre — vegetables, legumes, nuts, seeds, and wholegrains slow glucose absorption and support gut health. Aim for at least 30 g of fibre per day, in line with NHS guidance.

• Portion control — even healthy carbohydrates can raise blood sugar if eaten in large quantities. Using smaller plates and being mindful of portion sizes is a simple but effective strategy.

• Eating regular, balanced meals — skipping meals can lead to overeating later and erratic blood sugar patterns.

Weight loss is particularly important for many people with type 2 diabetes. Losing even 5–10% of body weight can produce significant improvements in HbA1c, and there is good evidence that substantial weight loss — for example, through a structured low-calorie programme — can lead to remission of type 2 diabetes in some people. Your GP or diabetes team can advise whether a structured weight management programme is appropriate for you.

Low-carbohydrate diets have attracted considerable attention and there is growing evidence — including from Diabetes UK — that they can produce significant reductions in HbA1c, particularly in the short to medium term. However, they are not suitable for everyone. People taking insulin or sulphonylureas must seek medical supervision before making major dietary changes, as dose adjustments will be needed to avoid hypoglycaemia. People taking SGLT-2 inhibitors should also seek advice before following a very low-carbohydrate diet, as this combination carries a rare but serious risk of euglycaemic diabetic ketoacidosis (DKA) — a condition where ketones build up dangerously even when blood glucose appears near-normal. A registered dietitian can help tailor an eating plan to your individual needs, preferences, and medicines.

How Physical Activity Affects Blood Sugar Control

Regular exercise improves insulin sensitivity and can meaningfully reduce HbA1c; NICE recommends at least 150 minutes of moderate aerobic activity and resistance training on two days per week for adults with type 2 diabetes.

Regular physical activity is a cornerstone of diabetes management and can contribute meaningfully to reducing HbA1c. Exercise improves insulin sensitivity — meaning your body's cells become more responsive to insulin and are better able to take up glucose from the bloodstream. This effect can last for several hours after a single session of exercise, and with consistent training, the benefits accumulate over time.

In line with the UK Chief Medical Officers' Physical Activity Guidelines and NICE guidance (NG28), adults with type 2 diabetes are advised to aim for:

• At least 150 minutes of moderate-intensity aerobic activity per week — such as brisk walking, cycling, swimming, or dancing

• Resistance or strength training on at least two days per week — such as bodyweight exercises, resistance bands, or weight training, which are particularly effective at improving glucose uptake in muscle tissue

• Reducing prolonged sitting — breaking up long periods of inactivity with short bouts of movement (even a 5-minute walk every hour) has been shown to help regulate post-meal blood sugar levels

It is worth noting that different types of exercise affect blood sugar differently. Aerobic exercise tends to lower blood glucose during and after activity, whilst high-intensity or resistance exercise may cause a temporary rise before levels fall. For people taking insulin or sulphonylureas, it is important to check blood glucose before and after exercise, be aware of the risk of hypoglycaemia during or after activity, and carry a fast-acting carbohydrate (such as glucose tablets or a sugary drink) to treat a hypo if needed. Discuss exercise management strategies with your diabetes team.

Safety considerations for specific complications:

• If you have peripheral neuropathy, wear well-fitting footwear and inspect your feet after exercise to check for blisters or injuries that you may not have felt.

• If you have proliferative retinopathy, seek ophthalmology advice before undertaking heavy lifting or high-impact exercise, as this may carry a risk of retinal haemorrhage.

• If you have cardiovascular disease or other complications, your GP or diabetes nurse can advise on safe exercise options tailored to your health status.

Starting gradually and building up activity levels is advisable, particularly if you have been inactive for some time.

Medicines Used to Reduce HbA1c in the UK

Metformin is the first-line medication for type 2 diabetes in the UK; SGLT-2 inhibitors, GLP-1 receptor agonists, DPP-4 inhibitors, sulphonylureas, and insulin are added based on individual cardiovascular risk, kidney function, and tolerability.

When lifestyle changes alone are insufficient to achieve target HbA1c levels, NICE guidelines (NG28) recommend the addition of glucose-lowering medication. The choice of medicine depends on individual factors including kidney function, cardiovascular risk, the presence of heart failure, weight, and tolerance of side effects. Treatment is always individualised and reviewed regularly by your GP or diabetes team.

Commonly prescribed medicines in the UK include:

• Metformin — typically the first-line medication for type 2 diabetes. It works primarily by reducing glucose production in the liver and improving insulin sensitivity. It does not cause hypoglycaemia on its own. Gastrointestinal side effects (nausea, diarrhoea) are common initially and can be minimised by taking it with food or using the modified-release formulation. With long-term use, metformin can reduce absorption of vitamin B12; your GP may periodically check your B12 levels.

• SGLT-2 inhibitors (e.g., dapagliflozin, empagliflozin) — these cause the kidneys to excrete excess glucose in the urine. They do not cause hypoglycaemia when used alone, but the risk increases if combined with insulin or sulphonylureas. Beyond glucose lowering, they offer important cardiovascular and renal protective benefits and are recommended by NICE for people with established heart disease, heart failure, or chronic kidney disease. Key side effects include genital thrush and urinary tract infections, and they can cause dehydration. A rare but serious risk is euglycaemic DKA — this is more likely during acute illness, surgery, prolonged fasting, or when following a very low-carbohydrate diet. SGLT-2 inhibitors should be temporarily stopped during serious illness, before surgery, and in other high-risk situations (follow your GP's sick-day rules). The MHRA has issued specific safety guidance on this risk.

• GLP-1 receptor agonists (e.g., semaglutide, liraglutide) — these mimic a gut hormone that stimulates insulin release and suppresses appetite. Most are administered by injection, but oral semaglutide (Rybelsus®) is also available in the UK. They are associated with significant HbA1c reduction and weight loss. NICE criteria apply to their use, and eligibility is assessed by your diabetes team.

• DPP-4 inhibitors (e.g., sitagliptin, alogliptin) — oral tablets that enhance the body's natural insulin response after meals. They are generally well tolerated with a low risk of hypoglycaemia when used alone.

• Sulphonylureas (e.g., gliclazide) — stimulate the pancreas to produce more insulin. Effective at lowering HbA1c but carry a risk of hypoglycaemia and weight gain.

• Insulin — used when other treatments are insufficient, particularly in type 1 diabetes or advanced type 2 diabetes. Various formulations are available and are tailored to individual needs.

All medicines are prescribed and monitored by your GP or diabetes team. Never adjust doses without professional guidance. If you think you are experiencing a side effect from any medicine, you can report it to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

Monitoring Progress and Setting Realistic Targets

HbA1c should be checked every 3–6 months when control is unstable; lifestyle changes typically take 8–12 weeks to be reflected in results, and targets should be individualised by your diabetes team.

Reducing HbA1c is rarely an overnight process. Most lifestyle changes take at least 8–12 weeks to be reflected in your HbA1c result, given that the test measures a weighted average over that period. Understanding this timeline helps set realistic expectations and prevents discouragement if early results do not show dramatic change.

In the UK, in line with NICE guidance (NG28), HbA1c testing is typically recommended:

• Every 3–6 months when treatment is being adjusted or blood sugar control is not yet stable

• Every 6 months once stable (this may be extended to 12 months in people who are very well controlled and where this is agreed with their diabetes team)

These tests are usually carried out at your GP surgery as part of your NHS annual diabetes review, which also includes checks on blood pressure, kidney function, cholesterol, feet, and eyes.

Tips for monitoring your progress effectively:

• Keep a food and activity diary — identifying patterns in your diet and exercise habits can highlight areas for improvement

• Use home blood glucose monitoring if advised — whilst HbA1c reflects longer-term averages, self-monitoring of blood glucose (SMBG) can help you understand how specific foods, activities, or stress affect your levels day to day. Flash glucose monitoring or continuous glucose monitoring (CGM) may be available for some people with type 2 diabetes on insulin — ask your diabetes team whether this applies to you

• Set incremental goals — a reduction of even 5–10 mmol/mol in HbA1c can significantly reduce the risk of complications. Celebrate small wins rather than focusing solely on reaching a final target

• Be aware of factors that can temporarily raise HbA1c — illness, stress, certain medicines (such as corticosteroids), and poor sleep can all affect blood sugar control

• Be aware of HbA1c limitations — if you have anaemia, a haemoglobin variant, CKD, or other conditions that affect red blood cells, your HbA1c may not accurately reflect your glucose control. Discuss this with your GP or diabetes team, who may use alternative measures

Targets should always be personalised — what is appropriate for a younger, otherwise healthy individual may differ from targets set for an older person or someone with multiple health conditions. Your diabetes team can help you interpret your results in context and adjust your management plan accordingly.

When to Seek Further Support From Your GP or Diabetes Team

Seek urgent medical attention for symptoms of DKA, HHS, severe hypoglycaemia, or a new foot ulcer; contact your GP promptly if HbA1c remains above target, complications are suspected, or you are planning significant dietary changes or pregnancy.

Whilst many people can make meaningful improvements to their HbA1c through self-management, there are circumstances where prompt or urgent professional input is essential. Knowing when to seek help is an important part of safe diabetes management.

Seek urgent or same-day medical attention if you experience:

• Symptoms that may suggest diabetic ketoacidosis (DKA) or hyperosmolar hyperglycaemic state (HHS) — these are serious emergencies. Warning signs include very high blood glucose, nausea or vomiting, abdominal pain, rapid or laboured breathing, fruity-smelling breath, extreme thirst, confusion, or drowsiness. Call 999 or go to your nearest A&E immediately if you suspect DKA or HHS.

• A new foot ulcer, wound, or signs of foot infection — redness, swelling, warmth, discharge, or an ulcer that is not healing should be assessed the same day, in line with NICE guidance (NG19) on diabetic foot problems. Do not wait for a routine appointment.

• Severe or repeated hypoglycaemia — if you or someone with you loses consciousness or cannot swallow, call 999.

Contact your GP or diabetes team promptly if:

• Your HbA1c remains persistently above your agreed target despite sustained lifestyle changes

• You experience frequent or troublesome symptoms of hypoglycaemia (shakiness, sweating, confusion, or palpitations)

• You notice symptoms that may suggest complications, such as changes in vision, numbness or tingling in the feet, increased thirst or urination, or unexplained weight loss

• You are considering significant dietary changes (such as a very low-calorie or low-carbohydrate diet) whilst taking insulin, sulphonylureas, or SGLT-2 inhibitors, as dose adjustments or medicine changes may be required

• You become pregnant or are planning a pregnancy — tighter HbA1c targets are recommended during pregnancy to reduce risks to mother and baby, and specialist preconception and antenatal diabetes services should be involved

• You are unwell with vomiting or diarrhoea and unable to eat or drink normally, as this can destabilise blood sugar control — follow your GP's sick-day rules guidance, particularly regarding SGLT-2 inhibitors and metformin

Specialist NHS support available to you: Beyond your GP, a range of NHS services can provide specialist support, including diabetes specialist nurses, dietitians, podiatrists, and structured education programmes. If you have been diagnosed with type 2 diabetes, ask about referral to a structured self-management education programme such as DESMOND (Diabetes Education and Self Management for Ongoing and Newly Diagnosed) or X-PERT Diabetes. If you have been told you have non-diabetic hyperglycaemia (prediabetes), the NHS Diabetes Prevention Programme (NDPP) offers evidence-based support to reduce your risk of developing type 2 diabetes. Asking for a referral to these services is entirely appropriate and can make a significant difference to long-term outcomes. You do not need to manage diabetes alone — a collaborative approach with your healthcare team consistently produces the best results.

Frequently Asked Questions