What is insulin resistance?
Insulin is a hormone produced by the pancreas that regulates blood sugar levels. It ensures that sugar (glucose) passes from the bloodstream into the body's cells, where it is used as energy. In insulin resistance, the cells respond increasingly poorly to insulin. As a result, the pancreas has to produce more insulin to keep blood sugar levels stable.
This condition can persist for many years without the fasting blood glucose being noticeably elevated. Left untreated, however, it can develop into prediabetes and later into type 2 diabetes. The risk of cardiovascular disease, fatty liver and certain hormonal disorders also increases.
Causes and risk factors
Insulin resistance usually arises from a combination of several factors. The most important include:
- Excess weight, particularly visceral abdominal fat
- Lack of exercise and a predominantly sedentary lifestyle
- A diet high in heavily processed carbohydrates, sugar and trans fats
- Genetic predisposition and a family history of type 2 diabetes
- Chronic stress and persistent sleep deprivation
- Hormonal conditions such as polycystic ovary syndrome (PCOS)
- Certain medications, for example long-term corticosteroid therapy
Age also plays a role: as the years pass, the insulin sensitivity of the cells tends to decrease.
Symptoms of insulin resistance: how can it be recognised?
Early insulin resistance often causes only non-specific complaints. Many of those affected do not initially take the signs seriously or attribute them to other causes. Possible indicators include:
- Persistent fatigue, especially after carbohydrate-rich meals
- Food cravings, particularly for sweets
- Problems with concentration and an "afternoon slump"
- Increase in waist circumference despite an unchanged diet
- Difficulty losing weight
- Skin changes such as dark, velvety patches in skin folds (acanthosis nigricans), for example on the neck or in the armpits
- Increased thirst and more frequent urination (rather late signs)
- In women: menstrual cycle disturbances or difficulty conceiving in the context of PCOS
If several of these symptoms of insulin resistance occur at the same time, medical assessment is advisable – especially if additional risk factors such as excess weight or a family history are present.
Testing for insulin resistance: diagnostic options
Several laboratory tests are available for diagnosis. The doctor usually combines several values to obtain a meaningful picture.
Fasting blood glucose and HbA1c
Fasting blood glucose shows the glucose level after at least eight hours without food. The HbA1c value (long-term blood sugar) provides information about the average blood sugar level over the past two to three months. However, both values may still be unremarkable in early insulin resistance.
Fasting insulin and HOMA index
A meaningful test for insulin resistance is the measurement of fasting insulin together with fasting blood glucose. From these two values, the so-called HOMA index (Homeostasis Model Assessment) can be calculated. An elevated value indicates reduced insulin sensitivity before blood glucose rises noticeably.
Oral glucose tolerance test (OGTT)
In the OGTT, blood glucose – and optionally insulin – is measured several times after drinking a defined sugar solution. This makes it possible to assess how the body responds to a sugar load.
Which tests are useful in each individual case should be discussed with the treating doctor.
Lowering blood sugar: what you can do yourself
The good news: in many cases, insulin resistance can be reversed if lifestyle is consistently adjusted. Studies show that even moderate changes can measurably improve insulin sensitivity. The focus is on diet, exercise, sleep and stress management.
Adjusting your diet
A balanced diet can contribute significantly to lowering blood sugar and improving the effect of insulin. The following have proven effective:
- Plenty of vegetables, pulses and high-fibre whole-grain products
- High-quality sources of protein such as fish, eggs, dairy products or plant-based alternatives
- Healthy fats from olive oil, nuts and seeds
- A clear reduction in sugar, sweetened drinks and white-flour products
- Mindful consumption of alcohol
Mediterranean-style diets are considered well researched and practical for everyday life in this context. Longer breaks between meals can also ease insulin levels – however, the specific implementation should be individually tailored.
Integrating exercise into everyday life
Physical activity improves the insulin sensitivity of the muscles immediately. The following are recommended:
- At least 150 minutes of moderate endurance exercise per week (e.g. brisk walking, cycling, swimming)
- In addition, strength training on two days per week, as muscle mass has a positive effect on sugar metabolism
- Short bouts of activity after meals, such as a 10- to 15-minute walk
Weight, sleep and stress
A reduction in body weight of just five to ten per cent can noticeably improve the metabolic situation. Equally important are sufficient and restful sleep (ideally seven to eight hours) and a conscious approach to stress. Relaxation techniques such as breathing exercises, yoga or meditation can be supportive.
Medication
If lifestyle changes are not sufficient, or if prediabetes or diabetes is already present, medication may be appropriate. This decision is made individually by the treating doctor, depending on the findings, concomitant conditions and tolerability.
When should you seek medical advice?
An assessment is particularly recommended in the case of:
- Persistent complaints such as fatigue, food cravings or unexplained weight gain
- Waist circumference above 88 cm (women) or 102 cm (men)
- A family history of type 2 diabetes
- High blood pressure, elevated blood lipid levels or fatty liver
- Menstrual cycle disturbances or suspected PCOS
An early diagnosis offers the opportunity to stabilise the metabolism and prevent secondary conditions. The sooner the signs are recognised and taken seriously, the better the long-term outlook.
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This article does not replace medical advice.