7 Reasons BMI is Bogus

Many people turn their weight loss or fitness efforts to a concept called Body Mass Index, or BMI. Body Mass Index measures your overall fat percentage on a fixed scale after specific measurements are taken. After considering these measurements and how they stack up to your weight and height, a number is assigned. There is considered to be one healthy range (usually anything under 25) and this is what people strive for in their muscle mass and overall measurements. However there are some that consider BMI to be a rather bogus claim and that this “one size fits all” measurement isn’t taking variances or body types into consideration. Here we look at why many feel BMI is not only an inappropriate measure, but even bogus in many cases.

7 Arguments Against BMI

Here are 7 of the top arguments against Body Mass Indexing.

1.It lumps all overweight or obese people into the same few categories. The problem with this is that there are varying degrees of being overweight as the excess weight is often distributed differently amongst individuals. That being said, to have one measure for everyone doesn’t take body type or other related factors into consideration.

2.It doesn’t take elements such as bone or muscle into consideration with its measurement. To go along with the different body types, a “one size fits all” type of approach doesn’t take into consideration the fact that some people have muscle that automatically makes them bulkier. An athletic body type for example may make somebody appear to be bigger or unhealthy if you look at their BMI alone.


3.It improperly classifies certain groups of individuals. For those who carry their weight in certain places, they may be classified as overweight when really they aren’t. Genetics certainly play a part in how people carry their weight or even gain their weight and you can’t fix one number to everyone without considering all of these factors.

4.It wrongfully benefits the insurance industry through higher premiums, often times unjustly assigned. When insurance companies look only at a BMI as some do, they are only getting one piece of the puzzle and this is not a fair measurement. This can cause inflated premiums for people who have a higher BMI number but who are in all reality perfectly healthy individuals.


5.It acts as one overall average when there are varying degrees and special circumstances that should be taken into consideration. Again it goes to show that everybody has an individual genetic pattern, make up, and ways in which they carry their weight. If you only take certain measurements and assign a given number to it, you are skipping over the many other factors that describe a picture of a person’s health.

6.It’s a method by which too many doctors or nutritionists put their faith into. There are some doctors or even nutritionists who use a BMI as their main source of measuring a person’s health and weight. This may result in improper diagnosis or unnecessary treatment if other factors aren’t taken into consideration. While BMI can certainly be a part of measuring the health of an individual, it certainly shouldn’t encompass the whole thing.

7.There’s no such thing as the “average” man or woman that it is mathematically based off of. The “average” woman is a size 14 but that’s not the “norm” that you see walking down the street. The point is that there’s no such thing as “average” because that’s just taking the population and dividing lines amongst it. A person can weigh more in theory but then in reality may carry a great deal of muscle mass with them. When we deal with averages such as BMI does, we get into dangerous territory.

With a little research, it appears BMI may not be all it&undefined;s cracked up to be.  Arguments such as these are important to consider if you are to weight your entire fitness and wellness program on this type of one-size-fits-all approach.

Mary Ward writes about various health care career topics, including how to obtain a masters in health care degree.

Your Comments

Jerry's picture

BMI does not precisely measure the percentage of body fat but rather sets an estimate of how much fat a person has. It is not considered a perfect method for judging someone's fat percentage. It is only used for screening purposes and how well a person develops or grows. The different categories signify if a person is normal, under or above the normal. If a person belongs to either under or above normal range, it means that there is a potential problem and there is a high risk of health problems that will occur. Knowing the BMI will help you make changes and adjustments in the lifestyle. It is still useful despite the fact that it is not precise. Other precise measurements are available if you want no bias result. 

Anonymous's picture

Why should we even accept BMI? It is easy to do. There is no other reason.

1. It was never intended to be used as a tool for individual diagnosis or evaluation, but to compare population A to population B for typical body weight based on height.

2. By using three physical measurements for men / four for women, the US Navy's bodyfat calculation actually gives a decently close measurement of body fat, instead of assuming that all pounds over X number are automatically fat. The fact that it does not rely on the scale (which cannot tell fat pounds from muscle / bone pounds) apparently is enough to dissuade people from using it because they are fixated on that number of pounds.

3. There is a difference between someone who lifts weights and exercises and gains 20 pounds of muscle, vs. someone who eats Twinkies in front of the TV and gains 20 pounds. There is a difference - that is, except to the BMI which decides that both of these people are eating the Twinkies.

4. The medical profession should be embarrassed and ashamed to misuse this 'tool' which is 'convenient' at providing a crap-shoot of a diagnosis. There is no excuse for us to have to be subjected to something that is quick, easy, and utterly unreliable!

Anonymous's picture

Jerry said regarding the BMI "Other precise measurements are available if you want no bias result." Yes, they are available, but of no use if your doctor, employer, or insurance company chooses to use the inaccurate but quick 'n' easy BMI nonsense. With much more accurate methods available which consider the INDIVIDUAL instead of making assumptions against a chart, there is no excuse for the use of the BMI as it is pervading our medical system today. Apparently however, convenience is seen as justification for quack medicine.

Bill's picture
To address point 7 by Astronutrition: Averages are never based on an "average" individual. An average is determined by looking at the data for an entire population. This is basic statistics. Is using BMI unfair? Well, they are only looking at statistical data that demonstrates an increased risk for certain diseases for people with BMI over 25. That data doesn't know whether you are athletic or are carrying excess fat. Point is - the numbers don't care. In other words, the numbers demonstrate that the reason for your being overweight in your BMI does not influence how likely you are or are not to be at risk. Your risk is statistically increased either way, through excess muscle or fat. We may not like that answer, but it is the one that the data is giving us.

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