Definition

Obesity (from the Latin adeps, meaning "fat"), also known as adiposity, is a nutritional and metabolic disorder characterized by being severely overweight. It is defined by an excessive accumulation of body fat, resulting in pathological health consequences. In casual language, it is often referred to as 'obesity,' which is also the common term used in English.

 

Diagnostic Criteria 

Overweight is assessed using the Body Mass Index (BMI), a measure defined by the World Health Organization (WHO). BMI is calculated as: (weight in kilograms) ÷ (height in meters)². A BMI between 18.5 and 24 is classified as 'normal weight.' A BMI of 25 to 29 indicates 'overweight,' while a BMI of 30 or higher is categorized as 'obesity,' where associated medical risks begin to increase. The WHO further divides obesity into three levels of severity. In children and adolescents, the classification of normal weight, overweight, and obesity is determined using BMI percentile curves. Overweight is defined as a BMI exceeding the 90th percentile, while obesity is defined as a BMI exceeding the 97th percentile, according to the S2 Guideline of the Working Group on Obesity in Childhood and Adolescence (2015). This guideline is endorsed by the German Society for Pediatric and Adolescent Medicine. ((Link)) (S2 Guideline of the Working Group on Obesity in Childhood and Adolescence, 2015, an association of the German Society for Pediatric and Adolescent Medicine)
 

Incidence

Obesity is an escalating global health issue, particularly in industrialized nations and rapidly developing economies. A 2010 representative survey of the Swiss population by the Federal Office of Public Health (FOPH) revealed that approximately 31% of adults in Switzerland are overweight, and 10% are classified as obese. The prevalence of obesity increases with age, particularly among men. Studies by the Swiss Health Promotion Foundation report that 12.9% of Swiss children are overweight, and 4.4% are classified as obese. These rates showed a significant increase until approximately a decade ago but have slightly declined in recent years. However, children of foreign nationals are disproportionately affected compared to Swiss children.

 

Risk Factors

In individuals with a genetic predisposition, overweight and obesity arise when energy intake exceeds energy expenditure. Factors contributing to this imbalance include high-calorie diets rich in sugary foods, soft drinks, or alcohol, coupled with insufficient physical activity—a common scenario in today’s sedentary lifestyles and reliance on motorized transportation. Even consuming otherwise healthy foods in excessive quantities can lead to weight gain. Emotional eating during periods of stress and the overabundance of sugary and fatty foods in modern diets further exacerbate the problem. Additionally, hormonal and metabolic disorders such as hypothyroidism, cortisol imbalance, and diabetes mellitus, as well as medications like psychotropic drugs, hormone therapies, cortisone, and antidiabetics, may also play a role.

 

Associated Symptoms 

The consequences of overweight and obesity predominantly manifest as metabolic disorders. Metabolic risk is influenced not only by BMI but also by fat distribution patterns. Abdominal fat deposits, particularly visceral adipose tissue surrounding internal organs (commonly referred to as the 'apple' body type), pose a significantly greater risk to fat and carbohydrate metabolism compared to fat distribution around the hips and thighs (the 'pear' body type), which is associated with lower risk. Metabolic complications include cardiovascular diseases, hypertension, diabetes mellitus, and lipid metabolism disorders, all of which negatively affect life expectancy. Obesity is also linked to increased risks of premature cognitive decline and dementia, including Alzheimer's disease. Additionally, obesity places substantial stress on the musculoskeletal system, and in pregnancy, it can result in gestational diabetes, with adverse outcomes for the child.