The Definition of Obesity

Obesity is a chronic, multifactor and complex disorder, which ensues due to the influence of genetic, metabolic and endocrine factors, as well as environmental factors. Obesity is now becoming one of the fastest growing pandemics of modern age, however, its global negative influence on the patient, and, on the society as a whole, is still not being objectively and completely valorised. The lifespan of a morbidly obese 25 year old is almost 12 years shorter than that of a healthy 25 year old. What is more, there is now a first generation of obese individuals whose expected lifespan is lower than that of their parents. Obesity is a disorder which is manifested by the excessive accumulation of fat within the body. The normal percentage of body fat is 20 to 25 % in women, and 15 to 20 % in men, out of the total body weight. Although there are more accurate methods of evaluating the excessive percentage of body fat, today, the most common method is the body mass index (BMI), which correlates well with the body fat index. It is calculated by dividing one’s weight in kilograms with the square root of one’s height in square meters (kg / m²). According to the World Health Organization (WHO), the body mass index ranging from 25 to 29.9 percent is defined as being overweight or as overnutrition, while BMI greater than 30 is defined as being fat or obese, and can be divided into three categories. Persons with BMI ranging from 30 to 34.9 belong to class I obesity, those with BMI ranging from 35 to 39.9 belong to class II obesity, while those persons whose BMI is above 40, belong to class III obesity. In order to make an additional assessment of the type of overnutrition within the clinical practice, waist circumference measurement is used. Any waist circumference higher than 94 centimetres in men and 80 centimetres in women is considered as the measure of central obesity and is treated as an isolated factor of risk for the development of cardiovascular disease, and overall health risk. Modern research has undoubtedly shown that there are significant differences between the composition and metabolic activity of body fat, depending on their location within the body. It is considered that the body fat within the abdominal cavity, which is located and situated between certain visceral organs, is a lot more metabolically active, therefore, represent a much greater danger to the overall health than the subcutaneous fat. The visceral adipose tissue secretes different factors and inflammatory cytokines, the so-called adipokines, which have a very important role in the pathogenesis of insulin resistance and the metabolic syndrome. The metabolic syndrome is a combination of visceral obesity, arterial hypertension, dyslipidemia and disorders of glucose metabolism. It is precisely the concept of insulin resistance that which represents a framework for understanding the connection of visceral obesity with other main factors of cardiovascular risk.