What is Prediabetes?
Understanding Prediabetes: What It Is & Why Early Action Matters
Raised Blood Sugar: A Warning Sign, Not a Diagnosis
A raised blood sugar result is a warning sign that your body is not managing glucose as well as it should, but it is not the same as a diagnosis of diabetes. Blood sugar levels can fluctuate for many reasons, including stress, illness, or certain medications. A single high reading does not necessarily mean you have diabetes, but it does indicate that further investigation is needed. Persistent high blood sugar levels, especially if confirmed by repeat testing, may suggest a higher risk of developing diabetes or other health complications. If you are concerned about your blood sugar levels, please consult your GP.
Blood Sugar Levels and HbA1c Ranges (UK Units)
Blood sugar is commonly measured by the HbA1c test, which reflects your average blood glucose levels over the past two to three months. In the UK, HbA1c is reported in mmol/mol.
HbA1c Range (mmol/mol) – What It Means:
- <42 – Normal
- 42 – 47 At risk (Prediabetes)
- 48 or above Diabetes (diagnosis)
An HbA1c between 42 and 47 mmol/mol (6.0–6.4%) means your blood sugar is higher than normal but not high enough for a diabetes diagnosis. This is often called prediabetes or non-diabetic hyperglycaemia. This is an important warning sign that you are at increased risk of developing type 2 diabetes.
Diabetes and prediabetes are increasingly common in the UK. Over 4.6 million people in the UK have been diagnosed with diabetes, with around 90% of these cases being type 2 diabetes and 8% type 1 diabetes [Diabetes UK, diabetes.org.uk].
Nearly 1.3 million people are believed to be living with undiagnosed type 2 diabetes. An estimated 6.3 million people in the UK have prediabetes (non-diabetic hyperglycaemia), meaning their blood sugar levels are higher than normal but not yet in the diabetes range. In total, more than 12 million people in the UK or about one in five adults are living with diabetes or prediabetes [Diabetes UK, diabetes.org.uk].
Without proper management, diabetes can lead to serious complications including heart failure, stroke, heart attack, and amputations.
If you have a raised blood sugar or HbA1c in the prediabetes range, it is a warning sign. However, with lifestyle changes and support, you can often reduce your risk and even reverse prediabetes before it progresses to type 2 diabetes. Regular monitoring and early intervention are essential to protect your long-term health.
Who’s at Risk?
Age, Weight, and Family History: Key Risk Factors
Certain factors significantly increase your risk of developing type 2 diabetes, many of which you cannot change. One of these factors is age where your risk of developing diabetes increases as you get older. Family history is also important as having a close relative (parent, sibling, or child) with diabetes makes you up to six times more likely to develop the condition yourself [Diabetes UK, diabetes.org.uk].
Weight is a modifiable but critical risk factor. Being overweight or obese increases your risk because excess fat, especially around the abdomen can make it harder for your body to manage blood sugar levels. Even people with a healthy weight but excess fat around the liver and pancreas may be at higher risk.
Lifestyle and Dietary Habits
Your lifestyle choices play a crucial role in your risk of developing type 2 diabetes. A sedentary lifestyle, spending long periods sitting or being inactive is linked to higher risk, even if you meet weekly exercise recommendations. Regular physical activity, such as brisk walking for at least 2.5 hours per week, can help reduce your risk.
Diet is equally important. Diets high in processed foods, sugary drinks, refined carbohydrates (like white bread and rice), and red or processed meats are associated with increased risk. Conversely, a healthy diet rich in fruit, vegetables, whole grains, and pulses can help lower your risk and support weight management.
Other modifiable factors include:
- Limiting alcohol intake to no more than 14 units per week, spread over several days
- Not smoking, as diabetes increases the harmful effects of tobacco
- Ensuring good sleep, as both insufficient and excessive sleep can increase risk
How We Can Help
We offer a comprehensive online dietetic service designed to help individuals reduce their risk of developing type 2 diabetes. Whether you have been diagnosed as prediabetic or are simply looking to reduce your risk of developing diabetes, our personalised guidance and support is provided by a registered dietitian. No GP referral is needed to use our service although you must meet our eligibility criteria to receive our services (see below).
For personalised professional advice and support, we offer an online dietetic assessment reviewed by a registered dietitian. For more information on this, please see our home page to get started.
Useful information
More information on Diabetes – Diabetes UK: What is diabetes? | Getting to know the basics | Diabetes UK
Diabetes Symptoms – Diabetes UK: Symptoms of diabetes | Type 1 and Type 2 | Diabetes UK