General Definition of Obesity
Obesity is generally defined as the abnormal or excessive accumulation of fat in adipose tissue to the extent that health may be impaired.
Measuring the level of adipose tissue and determining when it is likely to affect health is not an easy task.
Quantification of adipose tissue mass can be achieved by a number of laboratory methods including underwater body density measurement and body fat content estimated by dual energy X-ray absorptiometer.
In addition, the development of new techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT), has provided researchers with the opportunities to describe human adiposity in more detail.
However, most of these methods require costly equipment meaning that there is limited to clinical research setting.
In large scale population surveys and clinical/public health screening, an index of body weight adjusted for stature is commonly used as a surrogate for body fat content.
These indices are defined as different combinations of weight and height, such as weight divided by height or are defined as weight expressed as a percentage of mean weight divide by height or are defined as weight expressed as a percentage of mean weight for a given height and sex.
The most widely used in Quetelet’s index, better known as body mass index (BMI), which is body weight (kg) divided by height squared (meter square). This index has been shown to correlate weakly with height and strongly with body fatness in adults.
Determining the weight status status and level of adiposity in children and adolescent is even more problematical.
This is a stage of rapid growth and development.
During growth in childhood and adolescence, not only does height increase but body composition changes as well, thus classification of obesity according to a single measure is difficult.
In addition, international or regional weight status standards for children and adolescents may be less reliable as the age of onset of puberty and its associated physical changes often varies between different countries, ethnic groups or cultures.
General Definition of Obesity
