Is BMI an Accurate Predictor of Health

Is BMI an Accurate Predictor of Health?

A person’s BMI has been used as a standard health assessment for many years. However, it is now being criticized quite often as not really speaking what the health of a person is. Many in the medical profession consider this way of determining body health to be an oversimplification of what healthy really is.


The Body Mass Index was originally developed to quickly assess the obesity rate in individuals. The really quizzical aspect of this is that the Belgian mathematician who developed the BMI had also stated that although it was a good way of studying the population overall, it was not an ideal way of studying the health of an individual. The Body Mass Index is determined by dividing the weight by the person’s height.

The Body Mass Index chart ranges from underweight to extremely obese. The underweight is considered to have a high risk of poor health, as does the obese.

The extremely high risk for poor health is the extremely obese class, the very high risk for poor health includes those that are in the severely obese class. The normal weight and the slightly overweight are considered low and low to moderate risk of poor health.

Is it a Good Indicator of Health?

Is it a good indicator of health

Now it is obvious that this can give a quick view of a person’s health, but in terms of race and genetics, muscle mass, and bone density, can this method be relied on to accurately determine the risk of health?

Although there is much controversy over the method, it is true that poor health does increase with underweight or the obese, severely obese, and extremely obese classes. At these times, it may be recommended to change some aspects of one’s life. Such as diet and increased exercise.

Even with the amount of criticism as to the simplicity of health determination, many health providers still support the ability the BMI reading gives them to determine a person’s risk of serious health issues. This does not make the BMI a foolproof method, however.

There are other factors that should be taken into consideration when determining how accurate the Body Mass Index is, in regards to foretelling health.

Other aspects that are not taken into consideration include:

  • Age
  • Sex
  • Race
  • Lifestyle
  • Medical history
  • Genetics

The Downside of BMI 

The Downside of BMI 

Another set of factors that the BMI does not give an accurate view of is blood pressure, cholesterol levels, heart rate, blood sugar level, or inflammation levels. The same calculation is used for males and females with no regard to muscle mass. As people age, the muscle mass does diminish as the fat mass increases.

Other aspects not taken into thought or consideration for the BMI chart are socioeconomic and the ability to access healthy foods, mental well-being, living conditions, and knowledge and ability to prepare foods.

What this is pertaining to the most is that the lower-income or even mid-income families have a more difficult time affording nutritious foods due to the increased costs of such versus sugary, fast foods and heavily processed with artificial ingredients.

For the middle to lower class, it is more economical to purchase the not as healthy items as they can purchase more, enough to feed the family.

Determining Health Risks Based on BMI

Determining Health Risks Based on BMI

When it comes to determining health risks based on BMI, you could have two people side by side, exactly the same height, and weight, yet they look completely different. One may exercise more so has more muscle mass, while the other has a higher fat mass. However, based on the BMI method, they would be considered in the same health class.

It is possible that the distribution of a person’s fat mass may make a difference also. It is believed that those with a majority of fat mass in the stomach region are at a greater risk for poor health compared to those with the fat mass around the hips, buttocks, or thighs.

Some Doctors, also contributing authors to an article published in ‘Science’ have stated the need for a better method to measure fat and skeletal muscle, that these would be able to give a better look at the health risks of each individual person.

They say there is a need for better and more affordable tools to compute these measures that will help determine the healthier weight range for these individuals.

While at the same time, studies have shown that individuals with a higher BMI have a lower risk of cardiovascular risks. Also shows that those with a healthy BMI are metabolically unhealthy and have a higher mortality risk.

The Debate on How BMI Should Work

The Debate on How BMI Should Work

A Professor of Numerical Analysis for Oxford University has determined that the Body Mass Index chart currently in use is inaccurate in determining health. It will exaggerate how thin a short person is as well as exaggerating how fat a tall person is. He believes that the BMI divides by too much into short people and too little in those who are taller.

Other Doctors and Scientists believe that BMI should be more of a waist-to-height conversion method to determine risks of different health issues. Dr. Margaret Ashwell spoke in front of the 2012 Congress on Obesity in France. She states that a person’s waist measurement should be less than half their height in order to be healthier and have a longer life expectancy.

BMI’s Biggest Flaw

BMI's Biggest Flaw

What is considered to be the biggest flaw when using the standard Body Mass Index is that it does not take into effect that muscle mass weighs more than fat mass. As an example, the current BMI calculations would show that a person who sits around with no exercise and weighs 220 lbs, has the same BMI as a wrestler who weighs 220 and is the same height.

When looked at in this manner, it is scientifically the truth that the Body Mass Index does not work as it should. Using this previous example, the loafer who sits around and does no exercise is just as healthy as an athlete who works out continuously.

When looked at in this aspect, yes, there are serious flaws with the current BMI. Yet, the CDC, Centers for Disease Control currently state that the current Body Mass Index calculation is a fairly reliable method of determining obesity. Maybe they should explain that to the wrestler who is now considered overly obese, the same as what we would call a couch potato.

BMI for Athletes and Normal People

BMI for Athletes and Normal People

The National Health Institute also states that a good way to decide if your weight is healthy is to use the Body Mass Index chart. Both of these Health Institutions might want to reconsider what they are telling people.

This could be a reason why there are such issues concerning their weight for so many people. Those who are truly obese having the same BMI as a professional athlete are highly deceiving and will not benefit the couch potato who does not make an effort to be healthy.

However, it could be mentally detrimental to the athlete who had believed he is healthy and in the best shape of his life to be compared as equal to the couch potato. This could lead to harmful behaviors of various eating disorders such as anorexia, bulimia, or other negative behaviors that some people turn to when they want to lose weight.

Reality would be hurtful for the man who is having to face the fact that he is not as healthy as that professional athlete. As it should if he wants to have a long life expectancy. In a case like an example, I have given, changing the Body mass index to the one that Dr. Ashwell has suggested, where the waist measurement should be less than half the person’s height. This would work for males and females and be far more accurate when it comes to health.

Final Thoughts About BMI 

Final Thoughts About BMI 

Ultimately, what we have just learned is that the flaws of calculating one’s health by using the current Body Mass Index chart are numerous. The current method does not consider many of the important aspects of a person’s life. Things such as race, age, sex, ethnicity, and fat distribution.

This current method of determining obesity is also flawed seriously by using just the height and weight of an individual. Although muscle weighs more than fat mass, as shown in the example, an athlete who weighs 225 and is 6’2” has the same BMI as the person who is considered a couch potato and weighs 225 pounds and is 6’2”.

If you were to place these two individuals next to each other, it would give you a better visual as to what Dr. Ashwell is stating as grounds for developing a different Body Mass calculation. The suggestion that was given at the Obesity Council in 2012 was a completely logical one.

It is even more simple to calculate than the current method and would be far more accurate. Again, the example is given, the athlete may have a 35-inch waistline, and the couch potato could have a 42-inch waistline. Yet your current method of Body Mass calculations determines these two men to be the same.