Obesity (severe overweight)

Being obese, i.e. severely overweight can affect a person’s health, physical resilience and mobility. People with noticeable weight problems are also often vulnerable to prejudice and discrimination.

At a glance

  • A person is considered obese (severely overweight) if the percentage of fat in their body is excessively high.
  • Having a body mass index (BMI) of 30 or higher is considered obese.
  • Being severely overweight increases the risk of various chronic illnesses, such as diabetes, osteoarthritis and cardiovascular diseases.
  • It is therefore sensible for people who are obese and, in particular, very obese, to lose weight.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

Overweight and obesity: man wearing overalls standing in a crowd. His belly is hanging over the edge of the trousers to the right and left of the waistband.

What is obesity?

A person is considered obese (severely overweight) if the percentage of fat in their body is excessively high. This is the case if their body mass index (BMI) is over 30. Those who are obese have a higher risk of developing various chronic illnesses, such as diabetes, osteoarthritis and cardiovascular diseases. It is sensible for people who are obese and, in particular, those who are very obese, to lose weight. However, this is not easy for most of those affected. They need to be very committed, have plenty of perseverance and adequate support.

Overweight man sitting in a chair. A fat belly can be seen under the ribbed undershirt the man is wearing.

What causes obesity?

In most cases, people become severely overweight as a result of an energy imbalance. If more calories are consumed than are used up, the body stores the excess energy as fat.

Various factors can contribute to weight gain, for example:

  • diet and lifestyle
  • genetic predisposition
  • certain illnesses
  • psychological and social factors
  • certain drugs, for instance some psychotropic drugs and diabetes medication

Societal developments have also led to an increase in obesity rates. These days, fewer and fewer people are employed in jobs that require physical work, for example. This makes it more difficult for people to use up as many calories as they consume on a daily basis.

Various factors can contribute to people gaining weight including diet and lifestyle, genetic predisposition, certain drugs, illnesses and psychological factors.

At the same time people in industrial countries are surrounded on all sides by a large supply of food of all kinds. Many people regularly eat snacks such as sweets, potato crisps and nuts between meals, for example. A huge range of sugary drinks is also available. Alcohol, which contains even more calories than sugar, can also encourage weight gain.

The good news is that losing just a few pounds of weight can have a positive effect on health.

For more detailed information, for example about the causes of obesity, visit gesundheitsinformation.de.

How common is obesity?

According to figures reported by the Robert Koch Institute, about 24 percent of all men and women in Germany are obese. Of these, around:

  • 17 percent have class 1 obesity with a BMI between 30 and 35.
  • 5 percent have class 2 obesity with a BMI between 35 and 40.
  • 2 percent have class 3 obesity with a BMI over 40.
Around 24% of all men and women in Germany are severely overweight.

About 6 percent of all children and adolescents are obese. In the past few decades, the proportion of people who are very overweight has risen in all age groups.

How does obesity develop?

People do not suddenly become obese. Usually, obesity develops over years and decades. In most cases, obesity doesn’t occur until adulthood, often between the ages of 30 and 60. Many people do not move enough in their everyday lives and have less time for exercise once they start working or having a family. Over the course of their lives, other factors such as certain diseases can further encourage weight gain.

For women, pregnancy or menopause can trigger permanent weight gain. Although most mothers return to their pre-pregnancy weight after the birth, some women are unable to shift the weight they gained. It is not entirely clear why many women gain weight during menopause. Possible reasons include changes in hormonal balance and metabolism.

Obesity can also develop in childhood or adolescence. It is particularly difficult for people who are already obese when young to lose weight later in life.

How is obesity diagnosed?

Doctors consider someone with a body mass index (BMI) of at least 30 to be obese. BMI is a measure of a person’s weight compared to their height.

However, BMI provides no indication of how body fat is distributed. This is why waist circumference is also measured, roughly between the costal arches (bottom edges of the rib cage) and the iliac crests (curved areas on the sides of the hip bones). This is because fat on the abdomen (belly) poses a greater health risk than fat on other parts of the body. If the circumference is greater than 102 cm for a man or 88 cm for a woman, this indicates excessive abdominal (belly) fat. However, this doesn’t take account of the individual’s build or age.

In order to better judge the risk of complications, doctors should consider weight together with other factors, such as blood pressure, blood sugar, cholesterol and kidney values. 

Since conditions such as underactive thyroid can make obesity more likely, possible causes should also be determined. It can therefore be a good idea to determine thyroid levels. Otherwise, obesity can sometimes be too hastily attributed to poor diet or too little exercise alone.

Important: People who are severely overweight often find that doctors primarily treat the complications such as osteoarthritis or high blood pressure, while their weight problem stays in the background. To ensure that nothing is overlooked, it can be helpful for the person to write out questions that they would like to ask prior to going to see the doctor.

Why is high blood pressure dangerous?

The video below explains what happens in the body in the event of high blood pressure. What consequences can high blood pressure have and how can it be lowered?

This and other videos can also be found on YouTube.

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How is obesity treated?

People with obesity do not necessarily have to reach a specific BMI to improve their health. Depending on their starting weight, medical associations recommend losing 5 to 10 percent within 6 to 12 months.

Those who want to lose weight should make sure they establish a realistic plan to suit their needs. For some people, physical fitness and performance is their top priority, while others prioritize health reasons or the desire to feel better in their own skin.

To lose weight, the usual recommendation is a combination of more exercise and a change of diet. This can be supported by various weight loss programs, some scientifically proven and recommended by medical associations. However, they often have to be paid for by individuals themselves because they are considered more of a “lifestyle change” rather than treatment.

If a diet and exercise program is not enough, drugs can also help people to lose weight.

Not gaining weight again in the long term is often more difficult than losing weight in the first place. Processes involved in metabolism, hormonal balance and the central nervous system are responsible for this. Their main purpose is to maintain balance in the body. For example, losing weight reduces muscle mass and, as a result, the body’s energy requirement. This means that the more weight a person loses, the more difficult it is to maintain the new weight or lose more. Many people also find it difficult to permanently change habits and behaviors developed over many years.

Those who manage to successfully maintain a balanced diet and get enough exercise in the long term are most likely to avoid gaining weight again or to gain only a little. The most important principle to follow is that the number of calories consumed must not exceed the number that the body consumes.

Important: The good news is that losing just a few pounds of weight can have a positive effect on health.

Gastric surgery may also be an option for people who are very obese. As this type of procedure can be completely life-changing, it is important to carefully weigh up the pros and cons.

What else is important to know about obesity?

Often, people who are obese cannot get around very easily and are physically less resilient than others. In addition, being very overweight is at odds with the current ideal of beauty that is commonly portrayed on TV, in other media or in advertising, for example. This can have a negative effect on a person’s self-esteem and can inhibit obese people from appearing in public, playing sports or going to the swimming pool, for example. Some people with obesity therefore find it helpful to make a point of meeting other people in a similar position to exercise or play sports or to share their experiences in a support group.

Obesity may also be related to depression, eating disorders and other mental illnesses. In these cases, the problems should be examined together, rather than in isolation.

You can read real-life stories by people with obesity on the gesundheitsinformation.de website.

You will find information about self-help groups via a database on the website of the National Contact and Information Point For Encouraging and Supporting Self-Help Groups (Nationale Kontakt- und Informationsstelle zur Anregung und Unterstützung von Selbsthilfegruppen – NAKOS).

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen – IQWiG). As at:

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