Insulin resistance: causes, symptoms & nutrition

• Insulin resistance is considered a precursor to type 2 diabetes and can cause serious secondary health problems. Two-thirds of adults have symptoms.
• In addition to genetic predisposition, lack of physical activity, unhealthy diet, stress, lack of sleep, and excess weight play a central role.
• A balanced diet, weight reduction, regular exercise and stress reduction can significantly improve insulin sensitivity.
• Three structured main meals consisting of vegetables, protein and carbohydrates help keep blood sugar levels stable.
• Insulin also plays a role in fertility, for example in gestational diabetes or polycystic ovary syndrome (PCOS).
  

Without insulin, our body can’t function at all. It is a vital hormone produced in the pancreas and ensures that sugar (glucose) from the blood is absorbed into the body’s cells and used as an energy source. It therefore also plays a key role in absorbing and storing nutrients.

If this process is impaired, body cells no longer respond adequately to the hormone despite high insulin levels, meaning glucose is absorbed less effectively. This condition is known as insulin resistance.

Genetic predisposition increases the risk of prediabetes and type 2 diabetes – a chronic disease affecting blood sugar regulation. Long-term high blood sugar can lead to cardiovascular disease, nerve and kidney damage, and blindness.

The precursor, prediabetes, is becoming ever more widespread: a report by the American Diabetes Association, based on studies from 43 countries, shows that the global prevalence of impaired glucose tolerance in 2021 was 9.1 percent and is expected to rise to 10 percent by 2045 – which would mean 638 million affected individuals.

The International Diabetes Federation (IDF) estimates that, in 2021, more than 530 million people worldwide were affected by diabetes – with 6.7 million deaths worldwide believed to be directly linked to the consequences of this disease.

“We assume that about two-thirds of adults in Switzerland show at least one sign of insulin resistance – and the likelihood increases with age,” says John Schoonbee. He is the Global Chief Medical Officer at Swiss Re and has been working on the topic of metabolic health for years.

“Even ten years before prediabetes is diagnosed, insulin levels can rise, thus serving as an early warning system.”

Symptoms of insulin resistance may include:

• Persistent fatigue and lack of energy
• Food cravings, especially for sugary foods
• Weight gain (particularly abdominal)
• Difficulty concentrating
• Darkened patches of skin
• High blood pressure
• Elevated blood sugar and insulin levels
  

When body cells no longer respond to insulin, this can have several causes: genetic predisposition, hormonal changes or chronic inflammation. Chronic stress, lack of sleep, poor diet, and physical inactivity can also impair this important process.

In the case of insulin resistance, those affected can do a lot themselves by making lifestyle adjustments: this includes getting enough exercise and relaxation, maintaining a healthy diet, reducing stress and losing excess weight. According to the Federal Office of Public Health, 43 percent of the population is overweight or obese.

“In the early stages, a reduction of five percent of body weight can already significantly lower blood sugar levels and, in the best case, normalise them,” says Claudia Cavelti-Weder. She is a senior physician at the Clinic for Endocrinology, Diabetology, and Clinical Nutrition at the University Hospital Zurich.

“Studies have shown that about 50 percent of people with type 2 diabetes can lower their blood sugar through a combination of a low-carbohydrate diet and an adjusted lifestyle,” adds Schoonbee.

“If lifestyle changes alone are not enough, then we may also use semaglutides,” explains Weder. If insulin sensitivity is improved, the risk of type 2 diabetes can be significantly reduced – and fewer medications will be needed later: “In type 2 diabetes, insulin is always the last step.”

Healthy eating is a key factor for metabolic health. But why do we often find this so difficult? Melanie Sprenger is a nutritionist at the University Hospital Zurich and offers the following explanation: “Many emotions are regulated through eating. And most of the time, it’s not about knowledge, but about putting it into practice in everyday life.”

She is not a fan of strict prohibitions; instead, she advocates for long-term behavioural changes, such as a regular meal schedule of three main meals without snacks in between. Sweets are also allowed from time to time – ideally after a meal and consumed mindfully. And a short walk after a meal lowers blood sugar.

Sprenger recommends the plate model, which is promoted by the Swiss Society for Nutrition: “Ideally, half of the plate should be vegetables or salad, a quarter protein (meat, fish, cheese, tofu, etc.) and a quarter starches (rice, potatoes, pasta, bread, etc.) – along with plenty of water.

In practice, this could look like this: “You could top a plate of tomato spaghetti with two tablespoons of grated cheese and add a few cherry tomatoes or slices of zucchini to the sauce. Or you could snack on a few cucumber slices as well.»

Even for healthy people, the plate model is useful – in this case, the portions can be divided into one third each. “In this way, you not only improve your well-being but also actively contribute to a healthy metabolism and the prevention of numerous chronic diseases.”

Depending on energy needs, such as physical activities or sports, adjustments and possibly snacks may be necessary: “For example, fruit with quark or Darvida with cream cheese and cucumber.” In addition, sufficient exercise, stress reduction, and adequate sleep are essential.

A balanced diet is at the heart of a healthy metabolism. However, those affected can do even more to keep the metabolic system in balance by maintaining an active and well-balanced lifestyle.

Hormonal changes that occur during pregnancy can impair the effect of insulin and trigger insulin resistance. This, in turn, can lead to complications during pregnancy.

During pregnancy, a woman’s body has an increased need for insulin. If this cannot be produced sufficiently or used effectively, blood sugar levels rise, which increases the risk of high blood pressure. In addition, both mother and baby are at increased risk of developing type 2 diabetes later in life.

Treatment usually includes a tailored diet, regular physical activity and – if necessary – insulin therapy. In most cases, blood sugar levels return to normal after childbirth, but preventive care remains important.

Just as endometriosis often remains undetected and therefore untreated for a long time, polycystic ovary syndrome (PCOS) is also little known – even though 20 percent of women of childbearing age are affected.

In PCOS, the female body produces too many male hormones, which can lead to cycle irregularities, absence of menstruation, and lack of ovulation. Here, too, there is a connection with insulin: according to studies, up to 70 percent of all women with PCOS are insulin resistant. As a result, the diabetes medication metformin is often used in treatment.