Prediabetes is the precursor to type 2 diabetes – a condition in which blood sugar levels are elevated but have not yet reached the threshold for diabetes. It is the body's warning that something is out of balance. Approximately 10-15% of the German population has prediabetes, many without knowing it.

The insidious thing is that prediabetes usually causes no symptoms. You don't feel ill, you have no obvious complaints. But in the background, insulin resistance slowly develops, and the pancreas works harder than it should. Without intervention, about 15-30% of people with prediabetes develop overt type 2 diabetes within 5 years.

The good news: Prediabetes is reversible. Unlike established diabetes, you can not only stop its development, but often completely reverse it. Studies show that lifestyle changes can reduce the risk of diabetes by up to 58% – more effectively than any medication. The key lies in diet, exercise, and weight loss.

This guide explains what happens in the body in prediabetes, how to recognize it and – most importantly – how to avoid developing diabetes and restore your metabolism to balance with targeted measures.

To understand prediabetes, you need to know the mechanism of insulin resistance – the core process underlying the problem.

The normal system

After a meal, blood sugar rises. The pancreas releases insulin – the hormone that signals cells to absorb glucose. Muscle and fat cells absorb the glucose, blood sugar drops, and insulin production is reduced. A delicate balance.

The path to insulin resistance

Chronic calorie surplus, especially from sugar and refined carbohydrates, constantly requires a large amount of insulin. The cells become 'deaf' to the continuous insulin signal – they become less sensitive. The pancreas compensates by producing even more insulin. A vicious cycle: more insulin leads to more resistance, which in turn leads to more insulin.

What promotes insulin resistance?

Overweight, especially abdominal fat: Visceral fat (around the organs) is metabolically active and releases substances that promote insulin resistance.

Lack of exercise: Muscles are the main consumer of glucose. Inactive muscles respond less well to insulin.

Diet: High sugar, refined carbohydrates, and low fiber intake lead to constant blood sugar spikes.

Genetics: A family history increases the risk, but genes are not destiny – lifestyle can override genes.

Age: The risk increases with age, but lifestyle is the dominant factor here as well.

The exhaustion

Over time, the pancreas can no longer maintain the increased insulin production. The beta cells become exhausted, insulin levels decrease, blood sugar rises – prediabetes develops into diabetes.

Since prediabetes is usually asymptomatic, a blood test is the only way to diagnose it. These values ​​are crucial.

Fasting blood sugar (fasting glucose)

Measured after at least 8 hours without food. Normal: Below 100 mg/dl (5.6 mmol/l). Prediabetes: 100-125 mg/dl (5.6-6.9 mmol/l). Diabetes: 126 mg/dl (7.0 mmol/l) and above.

HbA1c (long-term blood sugar)

Shows the average blood glucose level over the last 2-3 months. Normal: Below 5.7%. Prediabetes: 5.7-6.4%. Diabetes: 6.5% and above. HbA1c is less affected by daily fluctuations and is therefore a more stable marker.

Oral glucose tolerance test (OGTT)

This test measures how the body reacts to a sugar challenge. You drink a defined sugar solution, and your blood sugar is measured after two hours. Normal: Below 140 mg/dl. Impaired glucose tolerance (prediabetes): 140–199 mg/dl. Diabetes: Above 200 mg/dl. This test is more sensitive and can detect prediabetes earlier than fasting blood glucose.

Who should get tested?

Risk factors that justify testing: Obesity (BMI > 25, > 23 for Asians). Age over 45. Family history of diabetes (parents, siblings). Lack of exercise. High blood pressure. Unfavorable blood lipids (low HDL, high triglycerides). In women: History of polycystic ovary syndrome (PCOS) or gestational diabetes. Dark skin discoloration (acanthosis nigricans) on the neck, armpits, and groin.

How often should I test?

With normal results and risk factors: Every 1-3 years. With prediabetes: Annually (to monitor progression).

Nutrition is the most powerful lever in prediabetes. It's not about a 'diet', but about sustainable changes that reverse insulin resistance.

Basic principles

Reduce glycemic load: Avoid sharp blood sugar spikes. This means fewer rapidly digestible carbohydrates and more slow-release, fiber-rich ones.

Increase your fiber intake: It slows down sugar absorption. Target: 25-30g daily. Sources: Vegetables, legumes, whole grains, nuts.

Protein with every meal: Stabilizes blood sugar and promotes satiety. Fish, poultry, legumes, eggs, dairy products, tofu.

Healthy fats: olive oil, nuts, avocado – they slow down gastric emptying and dampen blood sugar spikes.

What to reduce

Sugar and sweets: Obvious, but important. Also, be aware of 'hidden' sugar in sauces, processed foods, and drinks. Refined carbohydrates: White bread, white pasta, white rice, baked goods – they act like sugar. Sweet drinks: Cola, fruit juices, sodas – liquid sugar is particularly problematic because it doesn't provide a feeling of fullness. Highly processed foods: Often full of hidden sugars and unhealthy fats.

What do you prefer?

Vegetables in large quantities: the basis of every meal. Non-starchy vegetables (broccoli, bell peppers, spinach, tomatoes) have a minimal impact on blood sugar. Whole grains: instead of refined flour products. Oatmeal, whole-wheat bread, brown rice, quinoa. Legumes: lentils, chickpeas, beans – low glycemic index, high in protein and fiber. Nuts and seeds: a handful daily – healthy fats, protein, fiber. Berries: fruit with low sugar content and high antioxidants.

The order counts

Interesting tip: The order in which you eat affects your blood sugar. Vegetables and protein first, carbohydrates last – this can reduce blood sugar spikes by 20-30%.

Exercise is almost as important as diet in prediabetes. It improves insulin sensitivity directly and independently of weight loss.

Why exercise works

Muscles are the body's largest consumer of glucose. During exercise, muscles absorb glucose – even without insulin (insulin-independent glucose uptake). Regular training increases insulin sensitivity for 24-72 hours. Strength training builds muscle mass – more muscle means a greater capacity for glucose consumption.

The recommendations

At least 150 minutes of moderate activity per week – that's about 30 minutes on 5 days. Or 75 minutes of vigorous activity. Strength training 2-3 times per week for muscle building. The best combination is: endurance plus strength training.

What counts as moderate activity?

Brisk walking (so that you can still talk but not sing). Cycling on level ground. Swimming at a moderate pace. Gardening. Dancing. Tennis (doubles).

Strength training is important

Don't underestimate strength training. More muscle mass improves insulin sensitivity permanently, not just temporarily. You don't have to become a bodybuilder – 2-3 sessions per week with simple exercises (squats, push-ups, rows) are sufficient. A gym membership is optional – bodyweight exercises or resistance bands will do.

The timing trick

Exercise after eating (a 15-30 minute walk) significantly reduces the postprandial rise in blood sugar. A simple, effective strategy.

Reduce sitting

Even those who exercise regularly can suffer harm from excessive sitting. Get up every 30-60 minutes and walk around. Standing desks, walking meetings, active breaks – any interruption of sitting helps.

Obesity is the strongest modifiable risk factor for prediabetes. The good news: Even moderate weight loss has a significant effect.

Why weight is so important

Excess fat, especially abdominal fat (visceral fat), is metabolically active. It releases substances that: promote inflammation; increase insulin resistance; contribute to fatty liver disease; and disrupt hormonal balance. Reducing this fat improves all of these parameters.

How much weight loss is necessary?

Surprisingly little: Even a 5-7% weight loss reduces the risk of diabetes by about 58% (DPP study). At 90 kg, that's only 4.5-6.3 kg. More is better, but you don't need to reach your ideal weight. Small, sustainable reductions beat the big yo-yo effect.

Waist circumference as target measurement

Waist circumference is a good indicator of visceral fat. Increased risk from 94 cm for men, 80 cm for women. Measure at the level of the navel, in the morning on an empty stomach, and exhale calmly.

Sustainable strategies

No crash diets: They lead to the yo-yo effect and muscle loss. Moderate calorie reduction (300-500 kcal below your needs) is more sustainable. Prioritize protein: It protects muscles during weight loss and is very satiating. Utilize volume: Plenty of vegetables add volume without calories. Meal structure: Regular meals, less snacking. Tracking (optional): For some, counting calories helps – at least initially, to develop a sense of calorie intake. Think long-term: Change habits, don't just starve yourself in the short term.

Intermittent fasting

Intermittent fasting (e.g., 16:8) works well for some people with prediabetes. It can lower insulin levels and support weight loss. Not suitable for everyone, but it's an option.

Besides diet, exercise and weight, there are other factors that influence prediabetes.

Sleep

Too little or poor-quality sleep significantly increases the risk of diabetes. Sleep deprivation: Promotes insulin resistance. Increases hunger hormones (ghrelin). Reduces satiety hormones (leptin). Leads to increased cravings for sugar and carbohydrates. Goal: 7-9 hours of good-quality sleep. Observe sleep hygiene: Regular bedtimes, a dark bedroom, no screens before bed.

stress

Chronic stress increases cortisol – the 'stress hormone'. Cortisol promotes the release of glucose from the liver (for 'fight or flight'), thereby increasing blood sugar, promoting abdominal fat storage, and increasing insulin resistance. Stress management: meditation, yoga, breathing exercises, regular breaks, nature, social contacts, and exercise as a release.

Smoke

Smokers have a 30-40% higher risk of developing diabetes than non-smokers. Nicotine negatively affects insulin sensitivity. Quitting smoking is one of the most effective measures – even if it often leads to temporary weight gain.

alcohol

Moderate consumption appears to be neutral to slightly beneficial. However, excessive alcohol: provides empty calories, promotes fatty liver, disrupts sleep, and leads to cravings. For those with prediabetes: if at all, then only moderate amounts (1 drink for women, 2 for men per day).

Check medications

Some medications worsen glucose tolerance: corticosteroids, certain diuretics, and some antipsychotics. If you are taking any of these medications, discuss it with your doctor – do not stop taking them on your own.

Unlike established diabetes, prediabetes is often completely reversible. With the right measures, you can achieve normal blood sugar levels.

What science says

The groundbreaking DPP (Diabetes Prevention Program) study showed that lifestyle intervention reduced the risk of diabetes by 58%. This was more effective than metformin (31%). The core interventions were: 7% weight loss and 150 minutes of exercise per week. Even years later, participants in the lifestyle intervention group showed better results.

Timeframe for improvements

Insulin sensitivity improves within a few days to weeks with dietary changes and exercise. Measurable improvements in blood sugar levels occur after 2-3 months. With consistent adherence to the plan, normalization of blood sugar levels often takes 3-6 months. The goal is not just 'less bad', but truly normal blood sugar levels.

What 'healing' means

HbA1c below 5.7%. Fasting blood glucose below 100 mg/dl. Normal glucose tolerance in the oral glucose tolerance test (OGTT). This is achievable with lifestyle changes – no lifelong medication is needed if you remain consistent.

Relapse prevention

Important: The predisposition remains. Anyone who has had prediabetes once has a certain susceptibility. This means that lifestyle changes are necessary long-term, not just in the short term. Regular checkups remain advisable. Prediabetes can recur if old habits are resumed. However, the healthy habits that reverse prediabetes are the same ones that generally promote good health. It's not about 'deprivation,' but rather a better lifestyle.

Regular check-ups are important in prediabetes – to see progress and detect deterioration early.

Which tests are useful?

HbA1c: Shows the average blood sugar level over the last 2-3 months. Ideal for monitoring over time. Less affected by daily fluctuations. Recommended: Every 3-6 months for prediabetes.

Fasting blood glucose: Quick indicator. Can also be measured at home with a blood glucose meter. Gives you quick feedback on changes.

Self-monitoring

With prediabetes, continuous blood glucose monitoring isn't necessary like with diabetes. However, occasional measurements (e.g., with an inexpensive device from the pharmacy) can be informative: How does your blood glucose react to certain meals? Which foods cause spikes? How does exercise affect your blood sugar? This knowledge helps you make individual adjustments.

When to see a doctor.

If test results worsen despite lifestyle changes. If you experience symptoms such as increased thirst, frequent urination, fatigue, or blurred vision. Regular checkups every 3-6 months are recommended.

Conveniently from home

A doctor's visit isn't always necessary for basic checkups. The DoctorBox blood glucose HbA1c test allows you to easily determine your long-term blood glucose level from home. This way, you can monitor your progress and react early if necessary.

Prediabetes is not a sentence, but an opportunity. A warning from your body that you can use to change course – before a precursor becomes a chronic disease.

The key messages

Prediabetes is reversible: Unlike established diabetes, prediabetes can often be completely reversed through lifestyle changes. You can achieve normal blood sugar levels again.

Lifestyle beats medication: The research is clear – diet, exercise and weight loss are more effective than medication for prediabetes.

Small changes, big impact: Just 5-7% weight loss and 150 minutes of exercise per week reduce the risk of diabetes by 58%. You don't have to be perfect.

It's about habits, not diets: Sustainable changes in nutrition (less sugar, more fiber, real food) and regular exercise as part of life – that's the key.

Monitoring helps: Regular blood sugar checks show you whether your measures are working and motivate you to continue.

Your body wants health

The body has an amazing capacity for regeneration. Give it the right conditions – a balanced diet, regular exercise, sufficient sleep, less stress – and it will respond. Insulin resistance can improve, the pancreas can recover, and normal metabolic function is possible.

Prediabetes is a crossroads: one path leads to diabetes, the other back to health. You decide which direction to take.