Friday, 9 March 2012

Bodies and Masses and Index, Oh my!

So this week for my class, I was supposed to write about a controversy in my field - in my case, my field is healthy weight.

So, I have chosen to write about BMI and BFP!

BMI stands for Body Mass Index, BFP stands for Body Fat Percentage.

The two sides to the controversy are this:

Side A: The idea that BMI can be used as an effective tool for non-medical personnel to understand something about their weight, and if it is at a healthy place or not;

Side B: BMI is simply a diagnostic tool for medical personnel, and reflects little in terms of an individuals healthy weight., while BFP (Body Fat Percentage) is a significantly better and more realistic indicator of healthy weight.

So lets start with a quick background of both of these ways to measure the weight and height in comparison to each other. Where did they come from? Who invented them? How are they calculated?


Ancel Keys on the cover of Time
            Originally invented in the 19th century, called the Quetelet Index, it was relatively unused for very many years. However, in 1972 in the Journal of Chronic Diseases, Ancel Keys published an article called "Indices of Relative Weight and Obesity". In this article, he explored the different ways that body weight and height could be related to each other, and thereby confer some information to the doctor and/or the the patient. In exploring these relationships, he found that the ponderal index (height directly related to mass) is actually a fairly poor way to measure the healthy weight of an individual. However, according to Keys, the BMI (weight to height squared) is in fact the best indicator of healthy weight of those studied. (Keys)

There is a very important key word in that last sentence - that it was the best of those studied. As a debater, I have a tendency to see things like pretty easily. The medical community however, did not see that caveat. The result was that the BMI was utilized and became widespread through medical professionals.

This guy would probably be 'obese'
            The problem with BMI is essentially this - BMI utilizes averages of height and weight to determine if someone is on a healthy weight or an unhealthy. However, if someone is extremely muscular or very thin and wiry, they can often come in above or below their expected BMI, and in theory can therefore be termed 'obese' or 'underweight'. Quite obviously, this become problematic for athletes such as gymnasts, or people who are built rather heavy, but mostly of muscle. (Organization)

The biggest issue with BMI is that deals with averages based on populace, and doesn't make any kind of measurement of fat on the body, simply based on weight in relation to height.

It is also important to note that because of the average based importance of this type of study, it is good to be used as a population study, but not to be used for individual study.


It is unclear as to whom discovered how to calculate body fat percentage initially, however it is clear that there are very many ways to do it. From underwater weighing, to measurement with calipers, BFP gives a direct understanding of how much fat the individual has on their body, calculated as so:
Measuring Calipers

            Body Fat Percentage = (495/Body Density)-450 (Sports)

As you can see, it is body density that needs to be measured here, and that is what is measured through these various techniques.

General Body-fat Percentage Categories
Table of measurements relative to men and women

For men, your goal is between 2-24% body fat, which ranges from athlete to average BFP, while women aim for between 10-31% BFP, with the same scale. The reason for the difference is that men physiologically have more muscle and less fat than women, and as a result have lower indexes to worry about. (Muth)


To me, it is very clear. While BMI gives an excellent understanding of where you are in relation to other people, it gives a very small understanding of your own personal health. BFP gives an explicit number in terms of how much fat the individual has in their body, relative to the rest of their mass, regardless of their height.


Giant Greg Out.

Sources Cited

Keys, Ancel. Sciverse - ScienceDirect. Journal of Chronic Diseases, July 1972. Web. 7 Mar 2012. <>.

Organization, WHO. World Health Organization. World Health Organization, 1995. Web. 7 Mar 2012. <>.

Muth, Natalie. "What are the Guidelines for Body Fat Percentage Loss?". Ask the Expert Blog. American Council on Exercise, 2009. Web. 7 Mar 2012. <>.

Sports, TopEnd. "Testing Body Fat Percent". Top End Sports. Top End Sports, 2012. Web. 7 Mar 2012. <>.

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