Body Mass Index

Branson, NCI [Pub. Dom], WikiCom

Branson, NCI [Pub. Dom], WikiCom

The major components that contribute to body weight are bones, fleshy parts (mostly muscles), fats and fluids. Whereas the growth and ultimate dimensions and weight of bones are genetically determined; and the amount of body fluids controlled by the overall size of the body, the amount of muscles and fat tissue which a healthy person has at any given time, depends upon the life style and food habits of that person.

The proportion of body muscles and fat tissues should remain within a certain range in order for a person to enjoy healthy living. Scientists have developed an easy to use guide to calculate a person’s actual ratio of body weight and height. This guide is called the Body Mass Index or BMIIt is very handy for broadly determining whether a person is underweight, overweight / obese, or has a normal body weight..

Limitations of the BMI for adults

In spite of its immense value, however, the methodology adopted for calculating BMI is often questioned because human beings are not copies of a single edition. People come in different heights, shapes and sizes – even within a race or ethnic group. According to the NCBI, ‘The accuracy of BMI in diagnosing obesity is limited, particularly for individuals in the intermediate BMI ranges, in men and in the elderly.’

Having said that, and even while the health researchers are trying to perfect the BMI methodology, we can still use the available BMI for rating healthy and non-healthy body weight levels, to a considerable extent.

Limitations of the Percentile method to interpret the BMI for children and teenagers

Percentile method is currently being used in some countries for interpreting the BMI of children and teens (CDC). Here, one needs to be cautious. Percentile merely means the percentage of persons in a country (or globally) who come within the BMI level of a particular individual. The flaws in this type of percentile calculation are that, 1. the system takes all races or ethnic groups as a single entity; and 2. the system also includes markedly obese individuals in the calculation.

Assuming that there are 1000 teenage girls in a country and 600 of them are markedly obese, would it be logical to include these abnormal kids in the percentile calculation! It would be like combining the body temperatures of those individuals suffering from fever and those who are healthy, in working out the mean body temperature! If percentile is calculated after leaving out the clearly obese individuals, then the information would be more realistic and will give a more accurate picture of a child’s or a teen’s status of  general health.

The weight ranges that are unfavourable for healthy living are discussed under the subheads Obesity and Underweight.

Click below to visit other subheads related to your body.

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