The truth about BMI

August 21, 2017

This indicator might not mean with you think

Most American adults have heard of the term BMI or Body Mass Index. It has been an indicator for health since the 1800s. To find your BMI, you take your weight in pounds, divide it by your height in inches, and multiply that number by 703. According to American physicians, the resulting number places you in the following ranges of health:
  • Underweight: under 18.5
  • Normal: 18.5 to 24.9
  • Overweight: 25 to 29.9
  • Obese: over 30

While BMI has never been a perfect tool for measuring health, it was a free and easy way to get a general sense of health, especially in the early days. It’s a convenient means of collecting public health information on a wide scale. But according to a recent CNN article, it is important to understand the limitations of relying on BMI as a true indicator for quality of health. 

In recent years, more health professionals have been turning against this formula. The reason is, BMI doesn’t take into consideration different types of fat or qualities of fat that makes up an individual’s weight. It also can’t calculate the difference between fat and muscle weight. In other words, two different people can have the same BMI, but in reality, have significantly different health statuses. 

“BMI can be compared to a blunt tool that doesn’t take into consideration fat distribution, which is a critical marker of health risk. It is known that visceral or abdominal fat is far more damaging than peripheral fat, or fat around the hips and buttocks. Peripheral fat can actually be protective,” said Samer Mattar, MD, board-certified bariatric surgeon and medical director of Swedish Weight Loss Services, Bariatric, Metabolic, and Endocrine Center.

In addition to these limitations, BMI information is often inaccurate from the get-go because in population-wide surveys, the data is provided by the individual. It’s not uncommon for the information to be, at least slightly, off-the-mark. “People tend to underestimate their weight and overestimate their height, rendering BMI results that are less than real,” said Dr. Mattar. 

Why do medical professionals care about BMI, or body weight, in the first place? 

While body weight is not necessarily an indicator of disease, being overweight can be a symptom of metabolic dysfunction that is exhibiting as overweight. The presence of a high BMI can be an indicator of other silent, yet life-threatening diseases such as diabetes, hypertension, and sleep apnea, among other things, which should be medically addressed when present.

Therefore, despite its problems, BMI is still regularly used because it can be a useful data point. But informed individuals should recognize that it is a limited tool with several other variables coming into play to determine overall health. 

What should you do if you have a high BMI or are concerned about your weight?

The most important thing to do is to consult with your physician. Start a conversation about a health plan and related treatment options. This may include a referral to a multi-disciplinary metabolic and weight loss program. 

According to Dr. Mattar, “These programs offer numerous options and a continuum of care including lifestyle and behavior counseling, nutritional and psychological counseling, meal replacement therapy, drug prescriptions, and bariatric surgery which has proven to be a safe, effective and durable option in eligible patients.”

To learn more about our multi-disciplinary programs, visit our website. At Swedish, we are committed to working with patients as a team, with compassion, to reach every person’s optimum health.