An early sign of a serious disease

What are the symptoms of insulin resistance?

Insulin is a vital hormone that works like a key for our body cells. It ensures that sugar (glucose) from the blood enters the cells, where it is used for energy. Without insulin, glucose remains in the blood — and over time this can become dangerous.

With insulin resistance the body cells no longer respond as sensitively to insulin. The consequence: glucose stays in the blood and the pancreas produces more and more insulin to try to regulate blood sugar. The result is a chronically elevated insulin level — yet not enough glucose reaches the cells. Excess glucose is eventually stored as fat, especially around the abdomen.

Insulin resistance is considered a precursor to type 2 diabetes and is closely associated with other health problems such as the metabolic syndrome. It often develops gradually over years — and remains unnoticed for a long time because symptoms are non-specific or absent.

The symptoms of insulin resistance are varied and often subtle. Early signs include constant tiredness and lack of energy, because the cells do not get enough fuel. There is an increased craving for sweet foods or carbohydrates — often soon after eating — and weight gain, especially around the belly, because excess glucose is stored as fat. It is not uncommon to observe alternating loss of appetite and intense hunger.

Through increased thirst and frequent urination, the body tries to eliminate excess sugar. Some people suffer from nausea, abdominal pain and sudden vision deterioration, as well as dry skin, wounds that heal poorly and frequent infections, because elevated blood sugar weakens the immune system.

Many notice darkened patches of skin (acanthosis nigricans) in the armpits, neck and behind the knees, as well as more skin tags (also called “skin tags” or skin growths). Women complain of increased body hair (particularly on the upper lip and trunk), hair loss and a prolonged, irregular menstrual cycle. There can also be reduced fertility in women and erectile dysfunction or loss of libido in men. Psychological changes such as mood swings or depressive symptoms are also common.

Not every affected person shows all symptoms — and sometimes they only appear when insulin resistance has already progressed to type 2 diabetes. That's the tricky part: insulin resistance rarely causes clear complaints. Many people only find out by chance during a routine check-up. By then years may have passed — and the risk of complications such as diabetes, cardiovascular problems or obesity is already increased.

What causes insulin resistance?

If we eat too many rapidly digestible carbohydrates over a long period — table sugar, white bread, rice or sweets — the pancreas has to produce more and more insulin. At first this still works, but eventually the body cells become dulled and no longer respond properly to insulin. The result: the pancreas must release even more insulin to lower blood sugar. A vicious circle forms that often remains undetected for years. Several factors favour these processes.

Some people are simply unlucky with their genes: their cells are naturally less sensitive to insulin. If diabetes or insulin resistance runs in the family, it is worth being especially vigilant.

Overweight (especially abdominal) is another risk factor. Fat cells, particularly in the abdominal area, release signalling substances that interfere with insulin action. The more fat tissue, the harder it is for insulin to regulate blood glucose. According to studies, losing just a few kilos can improve insulin reactivity. However, thin people are not automatically protected: a study by the Institute for Preventive Medicine in Berlin showed that almost 25% of normal-weight women tested had signs of insulin resistance.

Regular physical activity makes cells more receptive to insulin again. Those who move little risk that their muscles take up less sugar and glucose in the blood remains high.

An unhealthy diet high in sugar, refined flour, fast food and saturated fats burdens the metabolism and promotes insulin resistance. Fresh vegetables, whole grains and healthy fats, by contrast, are real friends of insulin.

Stress hormones such as cortisol raise blood glucose. People who are continuously stressed or sleep poorly produce more insulin — and the cells become even less sensitive.

At certain stages of life, for example during pregnancy or with hormonal disorders such as PCOS, insulin action can be disturbed. Some medications (e.g. corticosteroids) can also reduce insulin sensitivity. Chronic inflammation in the body, infections or rare metabolic disorders can also impair insulin action.

Insulin resistance and diabetes: is there a connection?

Insulin resistance is an early stage in which the body already has difficulty managing glucose metabolism effectively. At this stage the development is still reversible. With the right diet, physical activity and a healthy lifestyle, cellular response to insulin can be improved. If insulin resistance remains untreated, the pancreas may become overworked and its insulin production exhausted. Then type 2 diabetes can develop — a chronic disease that can no longer be reversed.

Type 1 diabetes is an autoimmune disease that usually appears in youth and in which the pancreas no longer produces insulin. Insulin resistance and type 2 diabetes, by contrast, are closely linked and mainly affect adults. Not everyone with insulin resistance will automatically develop type 2 diabetes. However, people with insulin resistance have a fivefold increased risk of developing diabetes.

What role does nutrition play in insulin resistance?

A balanced diet can help improve insulin sensitivity and thus reduce or delay the risk of type 2 diabetes.

It is about choosing the right carbohydrates: not all carbohydrates are equal. In insulin resistance, favour complex carbohydrates with a low glycaemic index. These include whole grains, legumes and fresh vegetables. These foods release sugar slowly into the blood and thus prevent dangerous blood sugar spikes.

Fibre from fruit, vegetables, whole grains and legumes is not only good for digestion but also helps regulate blood sugar. Fibre increases satiety and supports cells to respond better to insulin.

Lean meat, fish, eggs and plant-based proteins like tofu or legumes are ideal glucose stabilisers. They fill you up without causing large increases in blood glucose — an important advantage in insulin resistance. Fats from processed foods and fatty meats, on the other hand, promote overweight and insulin resistance. Instead, opt for healthy fats from nuts, seeds, avocado and olive oil — they support metabolism and can reduce inflammation.

Short-term crash diets are not a solution for insulin resistance. They are often too restrictive, hard to maintain and frequently lead to the yo-yo effect. This further burdens the pancreas and insulin-sensitive cells. Much more important is a lasting dietary change tailored to individual needs. Studies show that diets such as the Mediterranean or DASH diet, as well as diets with a low to moderate glycaemic index, are particularly suitable. They help stabilise blood sugar and improve the cells' ability to take up glucose.

Another key element is the conscious management of sugar. Initially, a complete sugar abstinence can even make sense to relieve the body and reprogramme cravings.

What are the consequences of insulin resistance?

The most common consequence of insulin resistance is the development of prediabetes. Blood glucose is then higher than normal but not yet high enough to be classified as diabetes. In this stage, healthy eating, more exercise and weight loss can often achieve a great deal — prediabetes can even be reversed.

If prediabetes is left untreated, it can progress to type 2 diabetes. This is a serious condition in which the pancreas no longer produces enough insulin or the cells no longer respond to it. Type 2 diabetes can lead to numerous complications including kidney disease, cardiovascular disease and eye damage. These complications can severely affect quality of life and often require intensive medical treatment.

Insulin resistance is often associated with the so-called metabolic syndrome. This is a cluster of health problems. Typical features include high blood pressure, elevated blood glucose, excess abdominal fat, low levels of “good” HDL cholesterol and high triglycerides.

Insulin resistance can also damage blood vessels and thereby promote high blood pressure. Over time this can lead to vascular disease, nerve damage, kidney damage, heart attack and stroke.

Because glucose metabolism is closely linked with our brain, many affected people suffer from depression, anxiety or mood swings. Targeted treatment can often help alleviate these symptoms.

How does insulin resistance affect sleep?

Sleep and metabolism are more closely connected than many realise — especially regarding insulin resistance. Studies show that people with insulin resistance more often suffer from sleep apnoea — a condition in which breathing repeatedly stops during sleep. This causes sufferers to wake up frequently at night and feel unrefreshed the next day.

Disrupted sleep negatively affects insulin sensitivity. If you do not sleep well at night, your body responds worse to insulin, which further destabilises blood sugar. That in turn worsens insulin resistance.

This ongoing cycle of insulin resistance and poor sleep places a double burden on the body: metabolism suffers and recovery is insufficient. This leads to more fatigue, concentration problems and increased stress levels — factors that in turn negatively influence blood sugar.

Why is losing weight so difficult with insulin resistance?

The answer lies in the interaction between insulin and fat metabolism. In insulin resistance the insulin level is often chronically elevated. And that is exactly what makes losing weight so complicated: a high insulin level blocks the breakdown of fat tissue. Even if you eat less and reduce calorie intake, insulin signals the body to store rather than burn fat.

High blood glucose leads to increased insulin secretion. That means: the more sugar in the blood, the more insulin is produced — and the harder it becomes to lose fat mass. That is why avoiding blood sugar spikes to keep insulin low is so important.

Many diets focus only on calorie reduction — but with insulin resistance this is not enough. Without control of the insulin level you remain in fat-storage mode. This explains why many people with insulin resistance lose little weight despite dieting or regain weight quickly.

Losing weight with insulin resistance is challenging but by no means impossible. The key is to regulate insulin by mindful eating and avoiding blood sugar spikes. This can activate fat breakdown and enable long-term weight loss.

How does alcohol affect insulin resistance?

Interestingly, studies show that moderate alcohol consumption can lower blood glucose in the short term. That means a small glass of wine or beer can occasionally have positive effects on glucose metabolism. However, the maxim applies: “the dose makes the poison.” Alcohol should not be combined with sugary mixed drinks to avoid blood sugar spikes.

Conversely, drinking alcohol regularly or in larger amounts can negatively affect insulin sensitivity. That means body cells respond worse to the hormone insulin, which destabilises blood sugar and can worsen insulin resistance. Especially if you already have insulin resistance or belong to a risk group, monitor your alcohol consumption and discuss individual risks with your doctor.

Treatment: what to do about insulin resistance?

• Incorporate regular physical activity into your daily routine. Exercise — whether endurance or strength training — improves cells' insulin reactivity. Even daily walks help lower blood sugar and support weight loss.
• Avoid simple carbohydrates. Reduce consumption of white bread, sweets and sugary drinks where possible. They cause rapid blood sugar rises and promote insulin resistance.
• Prefer complex carbohydrates: choose whole grains, legumes and vegetables instead of refined flour or sugar. These foods raise blood sugar more slowly and prevent insulin spikes.
• Choose a fibre-rich diet. Fibre from fruit, vegetables and whole grains slows sugar release. It keeps you fuller longer and prevents cravings.
• Reduce carbohydrates. Less sugar in the blood means less insulin required. This helps ease metabolic strain and improve insulin sensitivity.
• Include oats and blueberries in your meals. Oats provide complex carbohydrates and fibre, blueberries supply valuable plant compounds. Both support balanced blood sugar.
• Opt for low-carbohydrate vegetables: zucchini, broccoli, spinach and the like provide many nutrients but little sugar. They are perfect daily satiating options.
• Choose high-quality protein sources such as seafood, lean meat or legumes. They help prevent post-meal blood sugar spikes, provide lasting satiety and curb cravings.
• Stick to regular meals. Three main meals a day help stabilise blood sugar. Snacks should be healthy and fibre-rich.
• Allow pauses between meals. Avoid constant snacking. This gives your metabolism time to recover and lowers insulin between meals.
• Pay attention to phytochemicals. Eat more plant foods like apples with skin, berries or broccoli. Phytochemicals such as quercetin support metabolism and may reduce inflammation.
• Use sweeteners selectively as sugar substitutes. Erythritol and xylitol are good alternatives as they minimally affect blood sugar. Enjoy sweets more consciously and avoid sugar spikes.
• Prefer a Mediterranean-style diet. This eating pattern is rich in vegetables, nuts, healthy fats and high-quality proteins. It keeps you full longer and stabilises blood sugar.
• Seek professional nutritional counselling. Individual guidance helps develop a personalised meal plan. This enables faster and more sustainable results.
• Research suggests intermittent fasting — such as alternate-day fasting or early time-restricted eating — can increase insulin sensitivity, often independently of weight loss. Consult your doctor before starting a fasting programme to find the method appropriate for you.
• Drink plenty of water and unsweetened tea. Avoid sugary drinks. Water and tea keep you hydrated and do not affect blood sugar.
• Consider medication. In advanced insulin resistance metformin may help regulate blood sugar. Always discuss the best treatment option with your doctor.
• Explore plant-based alternatives like berberine. This compound from barberry may, according to studies, improve insulin resistance. Consult your physician before taking herbal supplements.
• Keep vitamin D and magnesium in mind: deficiencies in these nutrients can worsen insulin resistance. Have your levels checked and discuss possible supplementation with your doctor.
• Combine exercise, diet and, if needed, medication. This combination of physical activity, healthy eating and (when necessary) medication is most effective. Insulin resistance can often still be reversed this way.
• Reduce stress and get enough sleep. Stress and lack of sleep increase blood sugar and impair insulin action. Relaxation and good sleep support your metabolism.
• First, be aware of your personal risk factors and take early signs of insulin resistance seriously. Regular checks — for example with home blood tests or medical examinations — help you intervene early and prevent long-term health problems.

Good news: you can do a lot yourself! With a balanced diet, regular exercise, sufficient sleep and stress management you can significantly improve your insulin sensitivity. By listening to your body and knowing your risk factors, you can often prevent or even reverse insulin resistance. Every step counts — start today!