October 27, 2026, 8:52 am | Read time: 3 minutes
Obesity affects millions of people in Germany and is often underestimated. The condition goes far beyond just a few extra pounds and can lead to numerous health consequences. But how does obesity actually develop, and what role do genes play in this form of pathological overweight?
Current figures from the Robert Koch Institute show that nearly one-fifth of the adult population in Germany is affected by obesity.1 This means around 13 million people suffer from the chronic condition, which places a lasting burden on the metabolism, cardiovascular system, and numerous other organs. “Overweight is a ticking time bomb for the body,” said Prof. Matthias Blüher, head of the Obesity Clinic for Adults at the University Hospital Leipzig, during the BILD Prevention Summit.
When is it considered obesity?
Doctors generally refer to obesity when a person has a body mass index (BMI) of 30 or higher.2 The BMI is calculated from the ratio of body weight to height. It’s not just the weight that matters. Fat accumulation, especially in the abdominal area, is considered problematic. The so-called visceral fat is particularly hormonally active and can promote inflammatory processes in the body.
Overweight is the result of disrupted metabolic processes
The notion that people with obesity just need to eat less still persists. However, experts believe this view is too simplistic. “That’s not true! Obesity is a disease partly caused by disrupted fat metabolism processes. Then, those affected can hardly resist their appetite,” explains Prof. Blüher.
In this context, so-called “food noise” can play an important role. This refers to constant thoughts about food that can influence eating behavior.
What role do genes play?
Genetic factors are indeed involved in many cases of obesity. According to experts, about half of all obesity cases are due to genetic causes. In most cases, changes in multiple genes work together. This means the risk of developing obesity is partly literally inherited.
Much less frequently, a change in a single gene is behind the condition. This affects less than one percent of cases. An example is the leptin gene, whose alteration can lead to a strong and hardly controllable feeling of hunger. “Those affected do not choose the disease. And at the same time, with every pound of overweight, the risk of life-threatening consequences increases,” warns Prof. Blüher.
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Obesity brings more than 200 secondary diseases
Obesity can affect almost the entire body. People with severe overweight have an increased risk for more than 200 diseases.
The excess fat reserves strain the metabolism and promote inflammation. This increases the risk of type 2 diabetes and hormonal disorders, among other things. At the same time, the additional weight acts as a permanent mechanical burden on joints, the spine, and breathing.
There are also often psychological and social consequences that negatively impact quality of life and can promote depressive symptoms. “Ninety percent of patients have at least one secondary disease, including orthopedic and psychological conditions,” notes Prof. Blüher.
What can be done for prevention?
A balanced lifestyle with a healthy diet and regular exercise can help reduce the risk of obesity. At the same time, experts point out that the condition cannot simply be attributed to a lack of discipline–because genes also play a role. Those who continue to gain weight despite their own efforts or regain lost pounds after a successful diet should have this medically evaluated.
Today, various treatment options are available. These include nutritional and exercise therapies, psychological support, and modern medications such as GLP-1 agents, often known as weight-loss injections or pills.