The traditional way of assessing obesity is measuring the body weight to the height of an individual. The best way of diagnosis of obesity is by calculating the Body Mass Index or BMI of an individual. The BMI determines whether you are overweight, obese or at an appropriate weight. The method of calculating body fat by BMI was developed by the Belgian statistician and anthropometrist Adolphe Quetelet. BMI is calculated by dividing the individual’s weight by the square of his/her height. BMI is expressed either in metric or US "Customary" units.
Thus in Metric system BMI = kg / m2
Where kg is the weight of the subject in kilograms and m is the height in meters.
In US/Customary system BMI = lb / in2
Where lb is the subject's weight in pounds and in is the subject's height in inches.
If the BMI of an individual is less than 18.5 he is considered underweight. Similarly a BMI of 25.0–29.9 is overweight, a BMI of 30.0–39.9 is obese, a BMI of 40.0 or higher is severely obese. BMI does not tell you whether your weight is composed of fat or muscles.
Waist circumference
BMI does not take into account differing ratios of obesity to lean tissue; nor does it distinguish between different forms of obesity. Increasing understanding of the biology of different forms of fatty tissue shows that visceral fat or central obesity in male or apple-type obesity has a much strongly related particularly with cardiovascular disease.
The absolute waist circumference of less than 102 cm or 40 inches in men and les than 88 cm or 35 inches in women or waist-hip ratio less than 0.9 for men and less than 0.85 for women are used to as measure central obesity.
Body fat measurement is an alternative way to determine obesity by assessing the percent of body fat. Men with more than 25% body fat and women with more than 30% body fat are obese. However, it is difficult to measure body fat accurately. Two simpler methods for measuring body fat are the skinfold test, which measures the fat beneath the skin by determining the thickness of the subcutaneous fat layer. Bioelectrical Impedance Analysis (BIA) can also determine the fat content in the body which is carried out at specialist clinics. However the routine use is discouraged by doctors. By calculating the electrical characteristics of fat and other tissues in your body one can determine the percentage of body fat. There are other blood tests like fasting levels of glucose, cholesterol and triglycerides, urine tests and other tests are effective ways of diagnosis of obesity. |
