Obesity

What is obesity?

Obesity is a chronic, complex disease characterised by an excessive build-up of body fat. Many factors can contribute to it, including genetic, hormonal, metabolic and environmental influences as well as lifestyle factors. Obesity is not just a cosmetic issue but a health condition that can significantly increase the risk of many chronic diseases and harm quality of life. The degree of obesity is most often measured with the body mass index (BMI), which is body weight divided by the square of height. In adults, a BMI of 25–29.9 kg/m² indicates overweight, and 30 kg/m² or above indicates obesity. However, BMI alone does not give a full picture of body composition or individual health risks.

What causes obesity?

Obesity usually has several interconnected causes. Although a long-term imbalance between energy intake and energy use plays a key role, the regulation of body weight is far more complex. Factors that can contribute to obesity include:

• Genetic and inherited factors
• Differences in hormonal and metabolic processes
• A high-energy diet and unhealthy eating habits
• A sedentary lifestyle
• Lack of sleep and long-term stress
• Certain illnesses and medicines
• Environmental, social and psychological factors

The development and persistence of obesity therefore cannot be traced back to individual lifestyle choices alone.

What health risks does obesity carry?

Long-term obesity can affect how many organ systems work and can increase the likelihood of various related conditions.

The most common health problems associated with obesity include:

• Type 2 diabetes: obesity can contribute to insulin resistance and problems regulating blood sugar.
• Cardiovascular disease: the risk of high blood pressure, coronary heart disease and stroke may increase.
• Lipid disorders: blood triglyceride and cholesterol levels may rise.
• Metabolic dysfunction-associated fatty liver disease: fat building up in the liver can cause inflammation and, over time, liver damage.
• Sleep apnoea: pauses in breathing during sleep can disturb sleep and reduce daytime performance.
• Musculoskeletal conditions: excess body weight can put significant strain on the joints, especially the knees and hips.

Obesity can also increase the risk of certain cancers.

What treatments are available?

Treating obesity requires a long-term, personalised approach. The main aim is not only weight loss but improving overall health, reducing the risk of related conditions and maintaining results over time. Treatment is based on lifestyle therapy, including a balanced diet, regular physical activity and methods that support behaviour change. In some cases medication may also be appropriate. In recent years there has been significant progress in drug treatment for obesity, especially medicines that influence appetite and fullness, such as GLP-1 receptor agonists and newer medicines acting on several hormonal pathways. In severe obesity, after appropriate medical assessment, bariatric or metabolic surgery may be considered. The right treatment strategy is always chosen based on the individual’s health, related conditions and treatment goals.

The role of clinical trials in treating obesity

Obesity is a major public health challenge worldwide, so research into more effective and safer treatments is a high priority. Clinical trials evaluate the efficacy and safety of new drug therapies, and examine how far new treatments can help with weight loss, improve metabolism and reduce obesity-related health risks. Researchers look at changes in body weight, blood sugar and lipid levels, cardiovascular risk factors, and the tolerability and possible side effects of treatments. Clinical research helps us better understand the biology behind obesity and supports the development of modern therapies that may improve the long-term health and quality of life of people living with obesity.