Why BMI is a bad measure of your health

healthy-woman-with-higher-bmi

By Hayley McKinnon

BMI is a big fat lie.

While everyone from your doctor to your insurance agency uses BMI (Body Mass Index ) to assess your general health, a growing body of research shows it’s an archaic system that fails to accurately measure body fat content or predict potential health problems.

In fact, using the BMI even creates problems for many women. Here’s what you need to know.

What is BMI and why is it supposed to be important?

BMI is calculated by dividing your weight by the square of your height. In theory, a BMI reading measures excess weight rather than excess fat, offering a simple and noninvasive way to classify people into different weight categories. Sounds straightforward, right?

Unfortunately, this traditional measurement system completely ignores variables that affect BMI – like muscle mass, bone density, body composition and gender – major factors that must be considered in any wellness evaluation. These variables are not necessarily indicators of poor health. In fact, the opposite is often true.

Here’s how wrong BMI can be

For those of us whose physical characteristics don’t necessarily fit the norm, a BMI reading is not just an inaccurate reflection of the state of your health. It also creates serious body image issues that can have a devastating effect on your self-esteem.

My little sister is an excellent example of the many shortcomings of the BMI measurement system. Emily has been swimming competitively since age seven, ranking among the best in the country throughout boarding school and leading her team to a National Championship as a college swimmer. Needless to say, she is a powerhouse athlete – whose size four frame is all muscle and lung capacity.

Yet, according to her BMI measurement, Emily is obese.

This is because the traditional BMI analysis fails to account for her muscular build and high bone mineral density, resulting in an inaccurate reading that defined her self image and damaged her confidence for years. On the BMI scale, a person with a score above 25 is considered overweight; a score above 30 classifies you as obese.

What’s more, Emily’s BMI reading also means that she has to pay unnecessarily high health insurance premiums, even though she’s healthier than the majority of the population.

Millions of people are in a similar situation. While the CDC suggests that BMI should not be used to calculate body fat, and only offers value as a predictor of potential health problems, doctors and health insurance organizations around the world rely on BMI readings as the “gold standard” for measuring obesity and assessing the state of your health.

This practice can have painful consequences for your bottom line – regardless of your waistline. According to the CDC, people with BMIs above 30 or 31 can expect a 25% increase in their insurance premiums; if BMI exceeds 39, they can be charged 50% more than an individual with a BMI of 25.

Better options than the BMI

We have several options that offer a more legitimate analysis of your health because they measure fat rather than weight. The body composition test measures your body fat percentage by comparing fat mass to total body mass. Other alternatives include the skin fold measurement and the bioelectric impedance test.

Skin fold measurement test
This is one of the oldest obesity tests still used in clinical practice today. Doctors use this method to estimate percentage of total body fat by measuring subcutaneous adipose tissue (the fat under your skin) in folds of skin. The patient’s age and gender are also factored into the results to ensure an accurate estimate of body fat.

Bioelectric impedance test
A non-invasive test that uses electrical signaling to measure the composition of your body, comparing the ratio of true body fat to lean muscle mass. As the electrode travels through the body, the BIA device measures how the electrical current travels through different types of tissues. This method paints an accurate picture of body composition, an important indicator of overall health and predictor of potential for disease development.

And revolutionary technology is coming soon…

The most revolutionary new technology is currently in development at The Mayo Clinic. It’s a 3D scanning application called the Body Volume Indicator. The BVI Pro will calculate weight distribution and amount of fat surrounding organs. By measuring a person’s body volume, rather than mass, the app can offer a more precise analysis of general health. The Mayo Clinic hopes that the BVI Pro will become the new gold standard of measurement by 2020.

So during your next check-up, ask your doctor to consider all of the factors involved in any measurement of good health – not just the select few that are used to calculate BMI. Standing up for yourself and your health by demanding alternatives analyses could have far-reaching implications for your health insurance costs, body image and overall health.

 

References
  • https://www.ncbi.nlm.nih.gov/pubmed/12181389?dopt=Abstract&holding=npg
  • https://www.nature.com/ijo/journal/v32/n6/full/ijo200811a.html
  • https://www.ncbi.nlm.nih.gov/pubmed/11165884?dopt=Abstract&holding=npg
  • https://www.ncbi.nlm.nih.gov/pubmed/11033983?dopt=Abstract&holding=npg
  • https://www.ncbi.nlm.nih.gov/pubmed/16418761
  • https://www.ncbi.nlm.nih.gov/pubmed/16895897?dopt=Abstract&holding=npg
  • http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(06)69222-2/fulltext
  • https://www.nature.com/ijo/journal/v32/n6/full/ijo200811a.html
  • http://onlinelibrary.wiley.com/doi/10.1111/ijpo.242/abstract

 

 

What to read next: Trying to lose weight? Skip your spin class by Dr. Sarika Arora, MD