Obesity: How dangerous is being overweight?


Obesity (obesity) affects a quarter of all adults in Germany and can be associated with severe physical and mental illness. What is the difference between obesity and obesity? What are the health consequences of extra kilos? And how can they successfully fight each other?

Obesity (obesity) is a chronic health disorder characterized by a pronounced increase in body fat and can promote various conditions such as type 2 diabetes, coronary artery calcification, depression and certain cancers. High obesity is one of the leading causes of death worldwide due to its complications. According to studies, approximately four million deaths per year are attributable to obesity.

How can obesity and overweight be calculated?

According to the World Health Organization (WHO), people considered to be obese have a body mass index (BMI) of at least 30. The BMI is the quotient of weight and height squared (kg / m²):

Calculation example: The BMI of a 1.70 meter tall person weighing 90 kilograms is 31.1 kg / m². 


 90 kg

———————- = 31.1 kg / m²

1.70 mx 1.70 m


Obesity is an increasing problem worldwide. According to a 2017 study published in the New England Journal of Medicine, which analyzed data for nearly 68 million children and adults between 1980 and 2015, the proportion of obese people in the world’s population has more than doubled in more than 70 countries. The nation most affected by obesity is the United States.

In Germany, about 24 percent of adults have a BMI of 30 and higher. For children and adolescents, the proportion is around six percent. The risk of overweight and obesity increases with increasing age.

Obesity is divided into severity levels. Pre-adiposity is a precursor; morbid obesity (also called adiposity permagna, grade 3 obesity, or morbid obesity) is by definition associated with a BMI of 40 or more. Sufferers affected by chronic comorbidities such as diabetes , lipid metabolism disorders, hypertension or respiratory distressing while sleeping, so a BMI from 35 is referred to as morbid.


categoryBody mass index


Risk for


normal weight18.5 – 24.9average


Obesity Grade 1

Obesity Grade 2

Obesity Grade 3

≥ 25.0

25.0 -29.9

30.0 – 34.9

35.0 to 39.9

≥ 40


slightly increased



very high

The BMI is only a guideline, which does not take into account factors such as gender, age, ethnicity, health and training status and stature of a person. For example, persons with fat pads in the abdominal area (apple type) have a higher risk of cardiovascular and metabolic diseases than people with overweight hips, thighs and buttocks (pear type). The critical limits for waist circumference are 102 centimeters for men and 88 centimeters for women. Physicians use as a measure the waist-to-hip ratio (Wahr-to-hip ratio, WHR), which should be below 0.8 for women and below 0.9 for men.

Separate calculation bases exist for obesity in children and adolescents, because these are still in growth: Here, the values ​​for height and weight are entered in a growth curve, which also takes into account age and gender.

In order to assess the individual health risk of an obese person, various medical examinations are necessary.

Causes: What can cause obesity and obesity?

Every person has an individual metabolic rate. This refers to the energy requirement of the body at rest, which depends, among other things, on weight, muscle density and metabolic activity. In general, overweight and obesity are caused by a disequilibrium in energy intake and consumption: as the body absorbs more energy (calories) than it does over time, body fat can build up.

The causes of overweight and obesity are manifold. Special risk factors include:

  • Genetic causes (familial predisposition): Children with severely overweight parents have a significantly higher risk of obesity. Twin studies suggest that susceptibility to obesity is genetic in 40 to 70 percent of all cases. In total, around 100 genes are currently identified that have an impact on BMI. Children are more prone to obesity if they have a very low or very high birth weight or if their mother has increased significantly during pregnancy.
  • Unhealthy diet: An unbalanced, high-sugar and high-fat diet can lead to weight problems in the long term. The high consumption of sugary drinks is also associated with an increased risk of obesity.
  • Physical Inactivity: Sedentary activity, low-activity leisure activities, and injuries, illnesses, or disabilities that restrict motor function reduce the basal metabolic rate.
  • Too little sleep: Studies show that even a sleepless night can lead to an unfavorable change in the energy metabolism. Lack of sleep leads to reduced glucose and increased protein consumption in muscle cells.
  • Stress: The release of cortisol leads to increased appetite.
  • Social status: According to studies, a lack of education and a low income are a barrier to prevent overweight.
  • Mood swings and depression: Mental problems are often associated with increased food intake for mood regulation and lack of exercise. People with obesity are often assumed to be weak-willed and lazy. Such stigmatization can lead to depressive and other psychosomatic disorders, which in turn are often regulated by increased food intake. There is a danger of a downward spiral.
  • Eating Disorders: A disturbance of eating behavior (for example, regular binge eating or eating at night) can lead to long-term overweight.
  • Constant availability of food : It is evolutionary in humans to create reserves – that is, to eat when food is available. An always available supply of food can be a problem.
  • Medicines: The use of various medications, such as antiepileptic drugs, antidepressants, hypoglycaemic agents, beta-blockers , glucocorticoids, neuroleptics and hormonal contraceptives may cause weight gain for a variety of reasons .
  • Metabolic Disorders : Thyroid disorders (for example, hypofunction) or other disorders of the metabolism (such as increased cortisol levels) are also possible causes of obesity.
  • Pregnancy: Pregnancy can disrupt the eating and exercise habits. Women who become overly pregnant during pregnancy are more likely to lose weight after giving birth .
  • Smoking cessation: Nicotine increases the metabolic rate by about 200 kilocalories daily and inhibits appetite. After smoking cessation normalizes the metabolism, which is why it often comes to slight weight gain. The problem is when sweets, soft drinks and snacks become substitute gratification.

Symptoms: What are the complications associated with obesity?

So far, obesity in the German health system is not recognized as an independent disease. However, it is clear that people with a BMI of 30 or higher have a lower life expectancy than normal weight: Statistically, a BMI of 30 to 35 can shorten life by up to four years, with a BMI of 40 to 45 it can be up to ten years , With increasing body weight, the risk of some dangerous concomitant or sequelae increases, which often begins creeping.

Often metabolic disorders occur that weaken the effect of insulin in the body ( insulin resistance ) and thus can trigger type 2 diabetes. High blood pressure, elevated blood lipid levels, arteriosclerosis, fatty liver , lipid metabolism disorders and sleep apnea (respiratory failure) can also be the result of obesity. These in turn are often triggers for strokes, heart attacks and other cardiovascular diseases.

Obesity is also associated with hormonal imbalances, infertility, chronic inflammation, certain types of cancer (such as tumors of the lining of the uterus, gallbladder and kidneys), dementia , gout , blood clotting disorders and diseases of the digestive tract, kidneys, bladder and musculoskeletal system (for example Arthrosis ).

The accident and surgery risk is also significantly higher in people with obesity. Many sufferers feel their weight severely affects their quality of life and develop psychosomatic disorders.

How does the doctor make a diagnosis?

First contact for obesity is the family doctor. He not only checks the general state of health, determines the BMI and hip and waist circumference, if necessary, but usually also initiates a blood and urine sample in order to be able to determine relevant laboratory values.

For history querying medical history and lifestyle part. Important are weight history, dietary tests, family history, risks for concomitant diseases (for example, the cardiovascular system), exercise, eating habits, family and professional environment and mental well-being.

Electrocardiography ( ECG , cardiac output measurement), ergometry ( exercise ECG ), echocardiography ( ultrasound examination of the heart), long-term blood pressure measurement, upper abdominal ultrasound (ultrasound) and sleep apnea screening (which is searched for nocturnal respiratory murmurs) can also be important studies. If necessary, the family doctor will refer you to the responsible specialists or recommend a nutritional outpatient clinic or an adiposity clinic.

Therapy: What to do with obesity?

Obesity as of obesity grade 1 is regarded as medically in need of treatment. If there are chronic illnesses, other physical side effects and risks or a strong feeling of suffering, therapy may also be necessary even in the case of preadipositas.

The treatment goal is a slow weight reduction (no radical diet) with subsequent stabilization of the ideal weight. Newly diagnosed type 2 diabetics often return to normal blood sugar levels simply by reducing the excess weight.

What is important is a realistic goal of the weight loss program, which is tailored to any comorbidities. As a rule of thumb for the amount of weight reduction over a period of six to twelve months, the following recommendations apply:

  • BMI 25 to 35 kg / m²: more than five percent of the initial weight
  • BMI> 35 kg / m²: more than ten percent of the initial weight

During pregnancy and addiction problems, no obesity therapy should be started.

Basic therapy for obesity: What is included?

A conservative treatment for obesity relies on three components that should be combined to increase efficacy:

  • Nutritional therapy : Reduction of calorie intake (approximately minus 500 kilocalories daily), for example, by reducing sugar, carbohydrates and fat.
  • Exercise therapy : Recommended are 30 to 60 minutes endurance sports on three to five days per week (medical recommendation and control). From obesity grade 2, sports that protect the joints ( swimming , aqua gymnastics) should be preferred . In addition, it is important to integrate a lot of movement (climbing stairs, brisk walking) into everyday life.
  • Behavior therapy ( psychotherapy ): The goal is a cognitive restructuring (harmful behaviors and thought patterns are replaced by positive ones). For example, the protected framework teaches long-term food handling, self-observation and control strategies and interpersonal conflict.

In the selection of conservative weight loss programs should be paid to a proof of scientific proof, since there are many commercially driven providers in this field. According to the German Network on Obesity (DNA), a serious basic therapy for obesity considers the following points:

  • The therapy should be long-term and last at least a year.
  • (Nutrition) physicians, diet therapist, sports or physiotherapist and psychologist (pedagogue) should work together in an interdisciplinary way.
  • The program should be accompanied scientifically.
  • The treatment must not require commercial weight loss products.

People with obesity, who are supported by family, partners and friends, are more successful in long-term weight loss.

Obesity drugs: When does the use make sense?

If no significant weight loss is achieved with diet , exercise and behavioral therapy (loss of less than five percent of the original weight within six months), the program may be supplemented with the use of medication under certain conditions.

In Germany (as of March 2019), the active substances liraglutide, naltrexone / bupropion and orlistat are approved for this, of which so far only orlistat, which inhibits the absorption of fat from the intestine, is recommended in the obesity guideline. Drug therapy should only be pursued if the user loses at least two kilograms in the first four weeks after starting.

Dietary supplements , which according to the manufacturers should help with weight loss, are in many cases ineffective. It is highly risky to take medicines for weight loss intended for the treatment of other conditions, for example, stimulants, drainage or hormones.

Obesity Surgery: What Methods and Risks Are There?

For obesity grade 2 and grade 3, surgical treatment for severe obesity may be considered. Prerequisites are that:

  • Conservative therapy has not led to relevant weight loss (within six months, loss of less than ten percent of the original weight)
  • the sufferer suffers from severe obesity comorbidities and
  • to a permanent diet change is ready.

Particularly well-established in obesity surgery (also metabolic or bariatric surgery) are the following surgical procedures:

  • Gastric Band: A (silicone) band is placed around the upper part of the stomach. If the divided part is filled, a feeling of satiety occurs. The surgery is reversible and the gastric band can be set to a different length via a tube connected to a fluid chamber placed under the skin.
  • Hood stomach : In this operation, about 70 percent of the stomach is removed so that the remaining stomach looks like a continuation of the esophagus and is filled quickly. Because the procedure also removes gastric cells that produce hunger-inducing hormones, the appetite also drops.
  • Gastric bypass: The surgeons make a small forestomach that can only absorb about 30 milliliters. An attached small intestine loop ensures that the digestive juices from the pancreas and bile are not supplied to the lower part of the small intestine, as these are necessary for absorption of the nutrients contained in the blood. After the procedure, vitamin and mineral supplements must be taken for life.

Obesity surgery has not insignificant risks: on the one hand, it can complicate as with any other surgical procedure to complications, on the other hand there are the risk of nutrient deficiencies, osteoporosis , digestive problems, intolerances and figure problems (excess skin) in gastric reduction and bypasses . From a physical perspective, psychological problems can also arise in the long term.

To minimize the risks, a certified obesity center should be chosen for surgical intervention . In addition, a long-term aftercare is important for the surgical success and securing the state of health of the operated.

Are there any alternatives to obesity surgery?

One method that does not involve a surgical change but that can produce a similar effect to gastric reduction is the gastric balloon : an endoscope is used to introduce a balloon through the mouth into the stomach which is filled with sterile saline and thus forms part of the stomach Gastric volume fills, leading to a premature satiety. Treatment with the gastric balloon is already approved for pre-adiposity. Because the balloon remains in the stomach for only six months (more recently twelve), it is important for the patient to adopt a healthier diet and lifestyle during that time. Otherwise, re-gaining weight after removal of the gastric balloon is likely.

The action of a gastric pacemaker is based on the fact that very overweight people usually have an increased stomach activity with rapid emptying, which leads to more hunger and higher calorie intake. The endoscope is used to fix sensors in the stomach wall, which are controlled by a computer (under the skin). Thus, among other things, the autonomic nervous system can be stimulated with electrical impulses, so that normalizes the stomach activity.

How is obesity going?

An obesity often begins in childhood or adolescence and then increases without successful treatment with the years (yo-yo effect). Which comorbidities occur depends on the extent and persistence of the overweight. Due to their high weight many sufferers have joint pain , so the mobility suffers. Also, shortness of breath and sweats are common symptoms.

The more overweight a person has, the harder it is to tackle it and the higher the risk of developing a so-called metabolic (metabolic) syndrome, which is the sum of the symptoms and risk factors for heart disease such as heart attack and stroke .

The higher the BMI, the shorter the statistical life expectancy of a person with obesity. Since it is difficult to fight against the pounds on their own, medical and therapeutic support in weight loss is essential. 

How can overweight be prevented?

A healthy, varied diet combined with lots of exercise and exercise is the best way to prevent obesity. It can be helpful to keep a nutrition and exercise diary and check body weight at regular intervals.

The diet should be rich in fresh, nutritious and high fiber foods such as vegetables, fruits and whole grains and low in highly processed, high-sugar, and spicy products such as sausages, chips, candy bars, sweets, ready meals, fast foods and white flour baked goods. It is advisable to enjoy animal products in moderation and to rely on vegetable origin in the supply of fats.

If you also drink a lot (at least 1.5 liters per day) and primarily on water or unsweetened herbal tea makes everything right.

So that the exercise is sufficient, it is advisable to cover as many distances on foot or by bicycle and to train the endurance.