Is your BMI lying to you?

Updated: Oct 6




BMI = Weight in kg/Height in meter squared

A simple ratio, yet a significant parameter to determine the health of a person. The BMI or Body Mass Index has become a quick way for doctors and insurance providers to judge whether a person is healthy. According to the Centre for Disease Control and Prevention, approximately one-third of all Americans have a BMI greater than 30, i.e., they are categorized as obese.


However, as mentioned in the International Journal of Obesity 2016, millions of people termed “obese” are healthy in terms of blood pressure, cholesterol, blood sugar, etc whereas people who fall within the healthy range are worse off. The births a question in our mind, is your BMI lying to you?

How can I calculate my BMI?

Calculating your BMI index is extremely simple. Consider your weight in kilograms and divide it by the square of your height in meters. A person with BMI lying between 18.5-25 is considered to be healthy whereas BMI less than 18.5 or greater than 25 categorizes the person as underweight or overweight respectively.

For example, if a person weighs 70kg and is 1.8m tall, their BMI would be 70/1.8*1.8 = 21.6, which falls under the healthy category. An easier way to calculate your BMI is by using the BMI calculators available online.

How does BMI affect your health insurance premium?

While BMI instinctively talks about the height and weight of a person, it fails to account the other conditions that affect the health of a person. Therefore, BMI isn’t an absolute indicator of your health. Nevertheless, insurance companies use BMI index to charge higher for people with higher BMI because obese policyholders are prone to illness and are likely to make more claims. Some of the diseases linked to obesity include heart disease and stroke, high blood pressure, diabetes, gout, cancer, gallbladder disease and gallstones, osteoarthritis, breathing problems and asthma.

Is body composition a more accurate indicator of overall health?

Body composition can definitely be a better indicator of a person’s health. However, it’s not accessible to everyone. While BMI can be calculated simply with your height and weight, calculation of body composition is a much more complicated process. The percentage of body fat in combination with overall weight is a greater predictor of morbidity or the chance of developing disease than weight or BMI alone.

What is the impact of incorrectly identifying someone as obese on their overall health?

BMI should neither be dismissed, nor should its importance be exaggerated. It is a common assumption that someone with a BMI of 30 is unwell. However, this is not the case always. Although excess weight has a long-term impact on a person’s health, classifying an obese person to be unhealthy wouldn’t always be right.

In conclusion, it’s safe to say that BMI can be a reliable first level indicator of a person’s health but it’d be misleading to categorise a person as healthy or unhealthy solely on the basis of their BMI index.