How to Lower Blood Sugar: Diet, Lifestyle & Meds

How to lower blood sugar safely is a question that matters for millions of people across the UK, whether they have been diagnosed with type 2 diabetes, identified as having pre-diabetes, or are simply concerned about their glucose levels. Persistently raised blood sugar can damage blood vessels, nerves and organs over time, yet with the right combination of dietary changes, physical activity and, where needed, medication, meaningful improvements are achievable. This article explains what drives blood sugar up, what the evidence says about bringing it down, and when to seek medical advice.

What causes blood sugar to rise and why does it matter?

Blood sugar rises when insulin production or action is insufficient, or carbohydrate intake exceeds energy needs, leading to hyperglycaemia that can damage blood vessels, nerves and organs over time.

Blood sugar rises when the body cannot produce enough insulin, cannot use insulin effectively, or when carbohydrate intake exceeds the body's immediate energy needs. Insulin, produced by the pancreas, acts as a key that allows glucose to enter cells for energy. When this process is disrupted, glucose accumulates in the bloodstream, a state known as hyperglycaemia.

Several factors can push blood sugar higher than normal, including:

• Eating large amounts of refined carbohydrates or sugary foods and drinks

• Physical inactivity, which reduces the muscles' ability to absorb glucose

• Illness, infection or surgery, which trigger stress hormones that raise glucose levels

• Certain medicines, including corticosteroids and some antipsychotics

• Poorly managed or undiagnosed type 1 or type 2 diabetes

Persistently elevated blood sugar matters because, over time, it damages blood vessels and nerves throughout the body. This increases the risk of serious complications including cardiovascular disease, kidney disease, sight loss, and peripheral neuropathy. Even moderately raised levels, sometimes called pre-diabetes (referred to in UK clinical practice as non-diabetic hyperglycaemia), carry long-term risk if left unaddressed.^[1]

In the short term, very high blood sugar can cause symptoms such as increased thirst, frequent urination, fatigue, and blurred vision. In severe cases, particularly in type 1 diabetes, it can lead to diabetic ketoacidosis, a medical emergency requiring immediate hospital treatment. In type 2 diabetes, very high blood sugar can cause hyperosmolar hyperglycaemic state (HHS), another serious emergency characterised by marked thirst, profound dehydration, and confusion or drowsiness; anyone with these symptoms should call 999 or go to A&E immediately. Understanding what drives blood sugar up is the first step towards managing it safely and effectively.

How can you lower blood sugar through diet and lifestyle?

Reducing refined carbohydrates, choosing lower GI foods, exercising regularly and losing 5 to 10 per cent of body weight are the most effective lifestyle strategies for lowering blood sugar.

Diet and lifestyle changes are the foundation of blood sugar management and can produce meaningful improvements in glucose control, particularly in people with pre-diabetes (non-diabetic hyperglycaemia) or early type 2 diabetes. NICE guidelines recommend structured education programmes and lifestyle intervention as first-line approaches before or alongside medication. UK programmes such as DESMOND (for type 2 diabetes) and DAFNE (for type 1 diabetes) provide structured support, and the NHS Diabetes Prevention Programme offers evidence-based lifestyle support for people identified as being at high risk.

Dietary strategies that support lower blood sugar include:

• Reducing refined carbohydrates and added sugars, such as white bread, sugary drinks, pastries and sweets, which cause rapid glucose spikes

• Choosing lower glycaemic index (GI) foods, such as oats, pulses, vegetables and wholegrains, which release glucose more gradually

• Eating regular, balanced meals to avoid large fluctuations in blood glucose throughout the day

• Reducing portion sizes, particularly of starchy foods, and increasing non-starchy vegetables

• Limiting alcohol, which can cause unpredictable swings in blood sugar, particularly in people taking insulin or sulphonylureas

Physical activity is equally important. Both aerobic exercise (such as brisk walking, cycling or swimming) and resistance training improve insulin sensitivity, helping muscles absorb glucose more efficiently. UK Chief Medical Officers' guidance recommends at least 150 minutes of moderate-intensity activity per week for adults, alongside muscle-strengthening activities on at least two days per week.^[14][15] People taking insulin or sulphonylureas should be aware that increased physical activity can raise the risk of hypoglycaemia; it is advisable to monitor blood glucose more closely and discuss any significant changes to activity levels with a GP or diabetes nurse before making them.

Weight loss, even modest amounts of 5 to 10 per cent of body weight, can significantly improve insulin sensitivity and reduce blood sugar in people with type 2 diabetes or pre-diabetes.^[3][9] Smoking cessation and stress management also contribute, as both smoking and chronic stress raise cortisol levels, which in turn elevate blood glucose.

For people exploring structured weight management support, Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online weight-management consultations, with prescriber review and pharmacist support, where clinically appropriate options may be discussed.

Which medicines does the NHS use to help lower blood sugar?

The NHS uses metformin as first-line treatment, followed by SGLT2 inhibitors, GLP-1 receptor agonists, sulphonylureas, DPP-4 inhibitors and insulin, chosen according to individual risk and tolerability.

The NHS uses a range of medicines to lower blood sugar in people with type 2 diabetes, with the choice depending on individual circumstances, kidney function, cardiovascular risk and tolerability. NICE guidelines recommend a stepwise approach, starting with lifestyle changes and, where needed, adding medication.

Commonly used medicines include:

• Metformin is usually the first medicine prescribed for type 2 diabetes. It works by reducing glucose production in the liver and improving insulin sensitivity. It is generally well tolerated, though gastrointestinal side effects such as nausea and diarrhoea are common when starting treatment.

• SGLT2 inhibitors (such as dapagliflozin and empagliflozin) lower blood sugar by causing the kidneys to excrete excess glucose in the urine. Beyond glycaemic control, NICE also recommends them for people with established cardiovascular disease, heart failure, or chronic kidney disease, where they offer additional organ-protective benefits. People taking SGLT2 inhibitors should follow individualised sick-day guidance, as these medicines should generally be paused during acute illness to reduce the risk of diabetic ketoacidosis.^[11]

• GLP-1 receptor agonists prescribed for glycaemic control in type 2 diabetes include semaglutide (Ozempic, for injection; Rybelsus, as a tablet), liraglutide (Victoza) and dulaglutide (Trulicity). These medicines mimic the hormone GLP-1, stimulating insulin release and reducing appetite. Tirzepatide (Mounjaro), a dual GIP and GLP-1 receptor agonist, is authorised by the MHRA both for type 2 diabetes and for chronic weight management.^[12][13] Note that semaglutide (Wegovy) and liraglutide (Saxenda) are separate products licensed specifically for weight management rather than for glycaemic control, and are not the same as their diabetes-licensed counterparts. GLP-1 receptor agonists should not be combined with DPP-4 inhibitors, as there is no meaningful additional benefit from using both together.^[7]

• Sulphonylureas (such as gliclazide) stimulate the pancreas to produce more insulin. They carry a risk of hypoglycaemia and weight gain.

• DPP-4 inhibitors (such as sitagliptin) have a more modest glucose-lowering effect and are generally well tolerated.

• Insulin is used when other medicines are insufficient, particularly in type 1 diabetes and advanced type 2 diabetes. Both insulin and sulphonylureas carry a risk of hypoglycaemia, and dose adjustments should always be made with clinical guidance.

All medicines should be taken as prescribed, and any concerns about side effects should be discussed with a GP or diabetes nurse.

How quickly should your blood sugar come down, and what is safe?

Blood sugar should fall gradually; lifestyle changes may lower fasting glucose within days to weeks, while HbA1c improvements become measurable over two to three months.

Blood sugar should come down gradually rather than rapidly, as a sudden large drop carries its own risks, including hypoglycaemia (low blood sugar) and, in people with pre-existing diabetic eye disease, a transient worsening of pre-proliferative or proliferative retinopathy associated with rapid glycaemic improvement.^[17][18] The appropriate rate of reduction depends on the individual's starting level, the cause of the elevation, and whether they are taking glucose-lowering medicines.

For most people with type 2 diabetes, NICE recommends target HbA1c levels (a measure of average blood sugar over approximately three months) of 48 mmol/mol (6.5 per cent) for those managed by lifestyle or a single non-hypoglycaemic drug, and 53 mmol/mol (7.0 per cent) for those on medicines that carry a hypoglycaemia risk. These targets are individualised and may be adjusted for older adults or those with complex health needs.

In practical terms, lifestyle changes may begin to lower fasting blood glucose within days to weeks, while HbA1c improvements typically become measurable over two to three months. Medicines such as metformin or SGLT2 inhibitors produce gradual reductions over weeks, whereas insulin can act within hours.

Signs of hypoglycaemia to be aware of include:

• Shakiness, sweating or palpitations

• Confusion or difficulty concentrating

• Hunger and light-headedness

If hypoglycaemia occurs, the NHS recommends consuming approximately 15 to 20 g of a fast-acting carbohydrate, such as glucose tablets or a small sugary drink, followed by a longer-acting snack such as a biscuit or piece of bread.^[10] Anyone experiencing frequent hypoglycaemic episodes should discuss their treatment plan with their GP or diabetes team, as dose adjustments may be needed.

When should you see a GP about your blood sugar levels?

See a GP if you have persistent symptoms such as increased thirst, frequent urination or fatigue, or if blood glucose readings consistently exceed your agreed target range.

You should see a GP if you have persistent symptoms of high blood sugar, such as increased thirst, frequent urination, unexplained fatigue, blurred vision or slow wound healing, particularly if these are new or worsening. A GP can arrange a fasting blood glucose test or HbA1c measurement to assess whether blood sugar is outside the normal range.

Routine monitoring is also important for people already diagnosed with diabetes or pre-diabetes. For people with type 2 diabetes, NICE recommends HbA1c testing every three to six months until levels are stable, and every six months thereafter. People with non-diabetic hyperglycaemia (pre-diabetes) are typically rechecked annually. If blood sugar targets are not being met despite lifestyle changes and medication, a GP or diabetes nurse can review the treatment plan.

Contact your GP promptly if you notice:

• Blood glucose readings consistently above your agreed target range

• Frequent episodes of hypoglycaemia, or hypoglycaemia that is difficult to treat

• New or worsening symptoms of diabetes complications, such as changes in vision, numbness or tingling in the feet, or swelling in the legs

• Significant weight changes or side effects from diabetes medicines

For urgent advice outside of GP hours, NHS 111 can provide guidance. If you or someone else develops signs of diabetic ketoacidosis, such as vomiting, rapid breathing, confusion or fruity-smelling breath, call 999 or go to A&E immediately, as this is a life-threatening emergency. Hyperosmolar hyperglycaemic state (HHS), which can occur in type 2 diabetes, is equally serious; symptoms include severe thirst, marked dehydration, and progressive confusion or drowsiness, and also require an immediate 999 call or A&E attendance. If you are unwell and have very high blood glucose, particularly if you have type 1 diabetes or take an SGLT2 inhibitor, check your ketone levels and follow the sick-day guidance provided by your diabetes team.

Suspected side effects from any diabetes medicine can be reported to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk. Reporting helps the MHRA monitor the safety of medicines used across the UK and contributes to ongoing pharmacovigilance.

Scientific References

1. Diabetes.
2. Treatment for type 2 diabetes.
3. Type 2 diabetes in adults: management (NG28).
4. Structured education programme | Type 2 diabetes in adults (QS209).
5. Initial medicines | Type 2 diabetes in adults: management (NG28).
6. Blood glucose management | Type 2 diabetes in adults: management (NG28).
7. Further medication | Type 2 diabetes in adults: management (NG28).
8. Dapagliflozin for treating chronic kidney disease (TA1075).
9. Type 2 diabetes | Treatment summaries – BNF.
10. Hypoglycaemia | Treatment summaries – BNF.
11. SGLT2 inhibitors: updated advice on the risk of diabetic ketoacidosis.
12. MHRA authorises diabetes drug Mounjaro (tirzepatide) for weight management and weight loss.
13. Tirzepatide.
14. Physical activity guidelines: UK Chief Medical Officers' report.
15. UK Chief Medical Officers' physical activity guidelines.
16. Abnormalities in Glucose Regulation During Antipsychotic Treatment. JAMA Psychiatry.
17. Worsening of diabetic retinopathy with rapid improvement in glycaemic control. Bain SC et al..
18. Early Worsening of Diabetic Retinopathy. JAMA Ophthalmology.
19. Retinal Outcomes in Diabetes: Antihyperglycemic Therapy, EWDR, and Perioperative Considerations. Biomedicines.
20. SGLT2 Inhibitors Reduce Heart Failure Hospitalization, Cardiovascular Death and Kidney Outcomes in Type 2 Diabetes. Diabetes, Obesity & Metabolism.

Frequently Asked Questions