How To Calculate Basal Metabolic Rate BMI

The body mass index (BMI) is a statistical measurement which compares a person’s weight height. However it does not measure the a person’s body fat but its helpful in determining the actual weight depending on the height of the person. It is a great tool to find out whether individuals are underweight, overweight or obese. 

The BMI was first developed by a Belgian statistician Adolph Quetelet and was initially known as the Quetelet Index. It was developed around1830 and 1850 in the course of social physics. It is also known as the Body Mass Indicator. BMI is an internationally used measure of weight to height.  

BMI is essentially described as the person’s body weight divided by the square of his or her height. This formulae usually used in medicines is kg/m2. One can also determine the BMI by using a BMI chart, which gives the BMI as a function of weight on the horizontal axis and the person’s height on the vertical axis using contour lines for different values of BMI or you can use different colors for different BMI categories.
The development of BMI and its usage date way back to the 19th century but the term BMI and its growing popularity is of a very recent date of 1972. BMI gained popularity especially in the Western countries with its people becoming more overweight and obese. However it has been said that it is very inappropriate for individual diagnosis. But nevertheless due to its simplicity it came to be widely used by individuals despite it inappropriateness.
BMI provided a simple numeric measure of a person's "fatness" or "thinness", allowing health professionals to discuss over- and under-weight problems more objectively with their patients. However, BMI has become controversial because many people, including physicians, have come to rely on its apparent numerical authority for medical diagnosis, but that was never the BMI's purpose. It is meant to be used as a simple means of classifying sedentary (physically inactive) individuals with an average body composition. For these individuals, the current value settings are as follows: a BMI of 18.5 to 25 may indicate optimal weight; a BMI lower than 18.5 suggests the person is underweight while a number above 25 may indicate the person is overweight; a BMI below 17.5 may indicate the person has anorexia nervosa or a related disorder; a number above 30 suggests the person is obese (over 40, morbidly obese). 
For a given height, BMI is proportional to weight. However, for a given weight, BMI is inversely proportional to the square of the height. So, if all body dimensions double, and weight scales naturally with the cube of the height, then BMI doubles instead of remaining the same. This result in taller people having a reported BMI that is uncharacteristically high compared to their actual body fat levels. This anomaly is partially offset by the fact that many taller people are not just "scaled up" short people, but tend to have narrower frames in proportion to their height. It has been suggested that instead of squaring the body height (as the BMI does) or cubing the body height (as seems natural and as the Ponderal index does), it would be more appropriate to use an exponent of between 2.3 to 2.7 
A frequent use of the BMI is to assess how much an individual's body weight departs from what is normal or desirable for a person of his or her height. The weight excess or deficiency may, in part, be accounted for by body fat (adipose tissue) although other factors such as muscularity also affect BMI significantly (see discussion below and overweight). The WHOregard a BMI of less than 18.5 as underweight and may indicate malnutrition, an eating disorder, or other health problems, while a BMI greater than 25 is considered overweight and above 30 is considered obese. These ranges of BMI values are valid only as statistical categories when applied to adults, and do not predict health. 
Some argue that the error in the BMI is significant and so pervasive that it is not generally useful in evaluation of health. University of Chicago political science professor Eric Oliver says BMI is an inaccurate measure of weight and that academics and doctors have taken the easy way out and that at a minimum the standards of who is overweight and who is not need to be changed and that the US population has been forced to fit into these standards. A 2005 study in America showed that overweight people actually had a lower death rate than normal weight people as defined by BMI.

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