What is Obesity?

Obesity is a condition of excessive fat accumulation in the body.  In terms of medicine, obesity is a condition of abnormal fat accumulation which is directly associated with many familial, genetic or environmental factors and may progress to many different diseases.  Obesity is the most important global problem of 21st century which causes chronic diseases and death.

World Health Organization (WHO) defines obesity as abnormal or excessive fat accumulation which causes diseases in the body.  Obesity is evaluated and classified with body mass index (BMI).  BMI is proportion of body weight per body length.  Its unit is defined as kg/m.

World Health Organization (WHO) accepts the BMI value between 20 – 24.9 kg/m2 as normal.  Obesity is defined as BMI of 30 kg/m2 and over while a BMI value between 25 and 30 kg/m2 as overweight.  BMI value of 40 kg/m2 and over may be defined as morbid obesity and a BMI value over 50 kg/m2 may be defined as super obesity.  Morbid obesity is an important health problem which should be treated because of importance and majority of severe diseases caused by morbid obesity.

World Health organization (WHO) reports that surgical methods are the most efficient and permanent methods for morbid obese patients with BMI of 40 kg/m2 and over even absence of an additional condition or problem; or in case of at least one of the additional diseases such as Type II DM, Cardiovascular Diseases, Sleep-Aonea Syndrome, Hyperlipidemia and Hypertension in patients with a BMI value between 35 and 39.9 kg/m2.

BMI is not sufficient solely for evaluation of obesity.  The patient is assessed by other measurements which shows lipoidosis ratio and distribution in the body mass.  Thickness of the skin fold, measurement of waist and hip circumference, waist/hip index (WHI) and some radiological examinations such as ultrasonography (USG), computed tomography (CT) and magnetic resonance imaging (MRI) may be performed to assess subcutaneous and intraabdominal lipoidosis.

Central Obesity- Apple Type Body Adiposity

Distribution of lipoidosis created by obesity is important for further risks.  Fats accumulated in the body, especially in the abdomen rather than arms and legs creates a high risk for metabolic syndrome (a chronic picture observed with cardiac diseases, hypertension, hyperlipidemia and Type II Diabetes Mellitus).  We call the body form with a fat accumulation in and around the abdomen as “apple type” body adiposity.  Patients with apple type obesity who have significant adiposity around the abdomen, carry a higher risk for metabolic syndrome.  Even the BMI is below the morbid obesity limit, patients whose WHR (Waist/Hip Ratio) is over 1 (WHR>1) should be monitored closely for metabolic syndrome.  Therefore, measurements such as waist circumference, abdominal circumference, hip circumference and thickness of the skin fold in some cases antropometrically as well as BMI are important for thickness of the skin fold.

Abdominal (waist) circumference over 94 cm in men and over 80 cm in women; waist/hip ratio over 0.95 in men and over 0.8 in women indicate a severe risk for cardiovascular diseases.  In addition to these findings of definition for metabolic syndrome by Adult Panel III, requirement of urgent treatment in individuals with abdominal circumference over 102 cm in men and over 88 cm in women has appeared.   If no treatment is applied, there is a higher, even a fatal risk for cardiovascular system disorders.

Generally, when risks of metabolic syndrome is discussed, we assess abdominal circumference differently according to the BMI.  Abdominal circumference measurements applied on obese individuals with a BMI value over 35 kg/m2 do not contribute significantly to the risk reflected by the BMI value.  In other words, BMI is sufficient to asses the risk for metabolic syndrome on individuals with a BMI value over 35 kg/m2.  However, BMI measurement only on individuals with a BMI value over 35 kg/m2 is insufficient to show the risks for metabolic syndrome and may cause ignorance of some patients.  Hip and waist circumference measurements must be performed on individuals with a BMI value below 35 kg/m2 and ratios should be considered.  Waist/hip ratios of the individuals who may be assessed as quite slim may be over one and monitoring of those patients in terms of cardiovascular diseses is very important.