Body Mass Index is measured by dividing an individual’s weight by the square of their height. It has been used as the standard determination of fatness and fitness since the 1970s.

I wanted to calculate my BMI along with cholesterol, blood pressure etc. to make sure that I’ve healthy-weight.  Because, having a low BMI does not mean you are healthy, as it doesn’t consider blood sugar or cholesterol factors in the results. That’s why it is important to have your BMI checked with other factors.

Unfortunately, this has been used to measure one’s health without considering other factors. Here are 6 myths about BMI that have been ‘infiltrating’ the public eye.

1. Eating Healthy

Believe it or not, muscle weighs more than fat. If you’re trying to build muscle or gain weight for health reasons, you have to eat more healthy, natural foods. Rebecca Puhl, PHD (deputy director of the Rudd Center for Food Policy and Obesity) says that even though people of different body sizes can still be healthy, many doctors “place blame on patients they see as overweight.” This means that healthy eating/exercise behaviors that work for one person give different results for someone else.

2. Used For Populations

A Belgian statistician created the BMI in the ‘70s. It was used to assess the collective weight of a particular population, not the individual. Unfortunately, this is what many doctors and insurance companies use the BMI for. This is because the formula was easy to calculate measures of fatness. A doctor or individual should never calculate their BMI, as it has no application for them.

3. High BMI = Heart Attack Risk

An alarming number of health studies draw associations between a high BMI and a risk of heart disease, high blood sugar, blood pressure, etc. Yet, a study was done on over 4,000 pairs of twins. The study revealed a number of twins with a BMI of more than 30 (thus making them “obese”, according to BMI standards) had no increased risk of a heart attack.

4. Lean Muscle or Fat?

As mentioned before, muscle weighs more than fat. It’s important to know that the BMI does not distinguish the two. The formula used calculates the weight and height of a population, not taking muscles, water weight or fat into consideration. Using the BMI’s standards, a bodybuilder who stands 6’ tall and weighs 250lbs. would be considered obese, even though the majority of that is pure muscle and he/she only has 5% body fat.

5. Health Measurement

As we’ve seen, the BMI doesn’t apply to everybody size in existence. Nor is it supposed to, as it was created to measure the body mass index of a populace. This is why a majority of health experts know that there is no way that the BMI could be used as an accurate source of measuring one’s health but can still be used to give an idea rather than nothing at all.

6. Low BMI = Healthy

Suffice to say that people with a high BMI are generally thought of having heart disease or are obese. On the other end of the spectrum, it’s generally believed that individuals with a low BMI are healthy. The truth is anything but: researchers used the BMI of ~40,000 adults and their cholesterol, blood sugar, blood pressure as well as their insulin levels. A large number of participants had normal numbers, despite being deemed “obese” on the BMI scale.


Thin people may be just as unhealthy as overweight people. The status of your health is determined by your genes, gender, lifestyle, diet and numerous other factors. If you’ve had a high BMI in the past, don’t panic based on that number alone!

Cite this article as:
Editorial Staff, "6 Myths About BMI (Body Mass Index)," in Medicalopedia, April 18, 2019, [Permalink:].