Pre-diabetes: what it means, whether it is dangerous, and how to reverse it

Pre-diabetes is a condition where blood sugar levels are higher than normal but not yet high enough to qualify as type 2 diabetes. Rather than being a diagnosis in itself, it functions as a warning sign — you are in, or close to, the borderline range, and taking action now can genuinely prevent the situation from progressing. Understanding what it means, what the risks are, and what you can do about it is the first step towards reversing it.

What is pre-diabetes?

Diabetes is caused by persistently elevated blood glucose levels, which arise when the body either becomes resistant to insulin or fails to produce enough of it. Insulin is a hormone produced by the pancreas that controls how glucose is absorbed from the bloodstream into the body's cells, where it is used for energy. When this process is disrupted — either because the cells resist insulin's signals or because the pancreas cannot keep up with demand — blood glucose remains abnormally high.

In pre-diabetes, blood sugar levels are elevated beyond what is considered healthy, but they have not yet reached the threshold that would warrant a diagnosis of type 2 diabetes. Think of it as a clear signal that the body's ability to regulate glucose is under strain, and that meaningful change is needed.

Does having pre-diabetes mean I will develop diabetes?

Not necessarily — and this is an important point. It is quite possible to reverse the situation. Many people who are diagnosed with pre-diabetes and make appropriate lifestyle changes do not go on to develop type 2 diabetes. However, people in this category are at meaningful risk, and the situation does require genuine effort to address. The good news is that the steps involved — regular exercise, a healthier diet, and modest weight loss where relevant — are achievable and bring benefits well beyond blood sugar control. The sections below explain exactly what those steps involve.

Symptoms of pre-diabetes

One of the challenges with pre-diabetes is that it usually produces no noticeable symptoms at all. Many people are diagnosed only when a routine blood test reveals elevated glucose levels. That said, there are some signs that can occasionally be present and that are worth being aware of.

Increased thirst is one possibility. When blood glucose is elevated, the body attempts to flush the excess sugar out through the urine, and this increased urinary loss of fluid can leave you feeling persistently thirsty. Related to this, some people notice that they are urinating more frequently than usual, particularly during the night.

Fatigue is another potential sign. When the body struggles to absorb glucose efficiently into cells, it can leave you feeling tired or low in energy even when you have rested adequately. Some people also experience blurred vision — this occurs because elevated glucose draws fluid into the lens of the eye, subtly distorting its shape and temporarily affecting how sharply you can see.

A less well-known but clinically significant sign is darkened patches of skin — a condition called Acanthosis Nigricans. These velvety, darkened areas typically appear around the neck, armpits, or groin. The mechanism is thought to involve insulin resistance driving excess insulin levels, which in turn stimulates skin cells to proliferate. Finally, some people notice unexplained changes in weight. This can occur because disruption to the body's ability to store and use glucose can affect how fat and energy are managed more broadly.

Is pre-diabetes dangerous?

Pre-diabetes is not as immediately concerning as a diagnosis of type 2 diabetes, but the evidence does show meaningful associated health risks, and dismissing it as unimportant would be a mistake. Research indicates that a significant proportion of people with pre-diabetes already have some degree of associated health problems at the time of diagnosis.

Hypertension — high blood pressure — affects approximately 36.6% of people with pre-diabetes, and raises the risk of both heart disease and stroke. Dyslipidaemia, meaning abnormal cholesterol or triglyceride levels, is found in around 51.2% — a figure that underscores the close relationship between metabolic health and cardiovascular risk. Albuminuria, the presence of protein in the urine that suggests early kidney involvement, is found in around 7.7% of people with pre-diabetes, while reduced kidney function affects approximately 4.6%.

In addition to these cardiovascular and renal risks, early pre-diabetes can also be associated with the very early stages of complications that are more commonly associated with established diabetes: early retinopathy (subtle changes in the blood vessels of the eye), early neuropathy (nerve involvement that can cause tingling or numbness, typically in the hands or feet), and early nephropathy (early-stage kidney involvement). These are not inevitable, and catching pre-diabetes at this stage is precisely the point at which intervention is most effective.

How do you check for pre-diabetes?

According to NICE guidelines, the diagnosis of pre-diabetes relies on two specific blood tests. The first is the Fasting Plasma Glucose test, which measures your blood glucose level after an overnight fast. A result between 5.5 and 6.9 mmol/l falls within the pre-diabetic range; values above this threshold are considered diabetic. The second test is the HbA1c, which reflects average blood glucose levels over the preceding two to three months. An HbA1c of 42–47 mmol/mol (6.0–6.4%) is classified as pre-diabetic; a result of 48 mmol/mol (6.5%) or above indicates type 2 diabetes. If you have not had either of these tests and you have risk factors for pre-diabetes — such as a family history of diabetes, being overweight, a sedentary lifestyle, or a history of gestational diabetes — it is worth discussing testing with your GP.

How to reverse pre-diabetes

The evidence base for reversing pre-diabetes is encouraging. There are several approaches, and most people benefit from combining more than one.

Regular exercise

Aim for 30 to 60 minutes of moderate-intensity physical activity on at least five days a week. Moderate intensity means exercise that makes you sweat and raises your heart rate, but still allows you to hold a conversation — brisk walking, cycling, swimming, and dancing all qualify. Research consistently shows that regular aerobic exercise reduces the progression from pre-diabetes to type 2 diabetes. Where possible, incorporating some resistance training — such as weights or bodyweight exercises — offers additional benefit, as building muscle mass improves the body's capacity to use insulin effectively.

Dietary changes

Diet is perhaps the most powerful lever available. The key principles are as follows. Reduce your consumption of refined carbohydrates and added sugars — this means cutting back on white bread, white rice, sugary drinks, sweets, and heavily processed foods, all of which cause rapid spikes in blood glucose. At the same time, increase your intake of dietary fibre, which slows glucose absorption and improves blood sugar control. Good sources include vegetables, whole grains, legumes, and fruits eaten with their skin on.

Choose complex carbohydrates over simple ones wherever possible: oats, brown rice, and sweet potatoes will raise blood sugar far more gradually than their refined equivalents. Reduce portion sizes — using a smaller plate is a simple, evidence-backed way to achieve this without requiring constant vigilance. Eat regular meals rather than skipping them, as going long periods without food can cause erratic blood sugar swings. Including a source of protein at each meal helps to slow digestion and stabilise glucose levels after eating. Avoid drinking your calories: fruit juices and sugary drinks cause rapid blood sugar spikes and offer minimal satiety. Foods with particular benefit include oily fish, nuts, seeds, avocado, olive oil, and leafy green vegetables. There is also good evidence that a formally structured low-carbohydrate diet — under appropriate guidance — can significantly reduce HbA1c levels.

Weight loss

For people who are overweight, even a modest reduction of 5 to 10% of body weight produces a significant reduction in the risk of progression to type 2 diabetes. The mechanism is straightforward: excess body fat — particularly around the abdomen — worsens insulin resistance. Losing weight reduces this resistance and allows the body to regulate blood glucose more effectively. This does not require dramatic weight loss to make a meaningful difference.

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Reducing sedentary time

Prolonged sitting has been shown to be harmful to metabolic health independently of how much formal exercise you take. Even if you exercise regularly, spending most of the remaining hours seated negates some of that benefit. Taking short breaks to stand or walk — even for just a few minutes every hour — makes a measurable difference to blood glucose levels throughout the day.

Stress management

Cortisol, the body's primary stress hormone, directly raises blood glucose levels by prompting the liver to release stored sugar into the bloodstream. Chronic stress therefore contributes to elevated blood sugar in a physiologically direct way. Techniques that are effective for managing stress — including mindfulness practice, yoga, and ensuring adequate sleep — are not merely good for general wellbeing; they are relevant to blood sugar control specifically.

Adequate sleep

Poor or insufficient sleep has been shown in research to directly raise blood glucose levels and reduce insulin sensitivity, even after just a few nights of disrupted sleep. If you have difficulty sleeping, this is worth addressing as part of your overall approach to reversing pre-diabetes — it is not a peripheral concern.

Is there medication for pre-diabetes?

In some cases, particularly where lifestyle changes alone appear insufficient or where the risk of progression to diabetes seems high, doctors may consider prescribing Metformin. This is a medication that has been used in the management of type 2 diabetes for decades and has an established safety profile. It works primarily by reducing the amount of glucose produced by the liver, and by improving the body's sensitivity to insulin. It is generally well tolerated, though some people experience gastrointestinal side effects — nausea, loose stools, or abdominal discomfort — particularly in the early weeks of treatment. These effects tend to diminish with time and are minimised by taking the medication with food. The decision to prescribe Metformin for pre-diabetes should always be made in consultation with your doctor, based on your individual circumstances, risk profile, and the degree of progress made through lifestyle changes.

Conclusion

Pre-diabetes is, in many cases, a reversible condition — and that is the central message. The evidence is clear that lifestyle changes, particularly regular physical activity and thoughtful dietary modification, can normalise blood sugar levels and prevent the situation from progressing to type 2 diabetes. The key is to treat the diagnosis as the opportunity that it is, rather than waiting to see what happens. If you have been told that your blood sugar is on the borderline, or if you are concerned about your risk based on your personal or family history, please do book an appointment to discuss this in detail. The earlier this is addressed, the better the outcomes.