BMI. We’ve all heard of it before, whether it be at the doctor’s office, on social media, or on the news. For some, it is just another statistic, but for others, it can become an unhealthy obsession. Let’s break down what BMI is, why BMI is not accurate, and how to stop obsessing over it.

What is BMI?

Before we break down why BMI is not accurate, let’s discuss what it actually is. BMI stands for body mass index. According to the CDC, adult BMI is calculated by dividing weight in kilograms by height in meters squared. This value is then used to classify adults into the following weight categories:

  • Below 18.5 = underweight
  • 18.5 to 24.9 = healthy weight
  • 25 to 29.9 = overweight
  • Above 30 = obese

History of BMI:

While a seemingly simple calculation, its origin has a dark past. The BMI calculation was invented by Adolphe Quetelet in the 1830s. Not a physician or trained in medicine, Quetelet’s work aimed to dissect the attributes of l’homme moyen or the “average man.” The Belgian mathematician held the belief that the average of a population is its optimal state. This led to the birth of the BMI calculation. Quetelet’s goal was to calculate l’homme moygen’s weight – the one every man should strive for. However, the population he studied to find the average weight only contained French and Scottish men. A formula that was specifically created for white Western Europeans quickly turned into a weight screening tool for all, with people of color, women, and other marginalized groups completely left out of the picture.

The BMI formula was born during a time when racist science was all the rage. Formulas, findings, and statistics were used to justify the systematic oppression of people of color. It is clear that the BMI was never meant to be used to measure body fat or health in diverse individuals in the 21st century.

BMI is not accurate

Why BMI Is not Accurate: we cannot know if someone is healthy from their BMI. 

Many people have had the way too common experience of a medical professional walking into the exam room, looking at their BMI and then telling them that you are overweight or obese. What then tends to happen, unfortunately way too many times, is the doctor telling someone it would be healthy for them to lose weight. This is regardless of age, race, lifestyle, or knowing anything about the person. This is using BMI as a measure of health, which it simply is not a good health measure.

The BMI is not an individualized measure of health and has many flaws. Here are some examples:

  1. Race and ethnicity

Since the BMI ranges were calculated with a white male only population, the same ranges do not hold true for people of color. A 2003 study aimed to measure what BMI caused people of different races to live the longest. The results indicated that Black people with a BMI of 23 to 30 tend to live the longest. Therefore, Black people with a higher BMI are not necessarily at risk for more health concerns.

The traditional scale indicates that for white people, a BMI of 30 is associated with metabolic syndromes such as heart disease, stroke, and diabetes. However, in Indian patients, this number is closer to 27 and is even lower in Taiwanese patients, according to Dr. Saniea Majid, M.D. For non-white patients in particular, using BMI as an accurate indicator of health-related risks can be incredibly misleading. This doesn’t even take into account that the BMI is one measure alone, and we can’t use one measure to determine health.

  1. Age

As we get older, our bodies tend to store more fat and retain less muscle mass. Our natural body changes will cause BMI scores to rise with age. Some claim that the optimal BMI for older people is between 25 and 27 (falling in the overweight range). Having a slightly higher BMI above the age of 65 can even protect against certain health issues such as osteoporosis and sarcopenia.

  1. Muscle Mass

One of the main criticisms of BMI is that it does not differentiate between fat and muscle mass. Since muscle tissue is more dense than fat, people with a high percentage of muscle mass such as athletes are technically considered overweight on the BMI scale even though their body fat percentage is low and their health is not at risk. Even non-athletes who enjoy regular weight training and building muscle may see their BMI increase as a result. However, this is not a cause for concern as the scale and BMI would have you believe.

  1. Weight distribution

BMI only takes into consideration two factors – weight and height. However, the way in which weight is distributed can have a significant influence on one’s health. For example, let’s say Matt and Dale both have a BMI of 23. Matt carries most of his fat in his waist, while Dale carries most of his weight in his legs. Although their BMI would indicate they are alike in terms of health, Matt statistically is at a greater risk for developing metabolic and cardiovascular diseases compared to Dale. A 2017 study done by the Radiological Society of North America found that where fat is stored in one’s body, rather than the overall amount of fat, is what increases risk of heart attack, stroke, and diabetes. Again, it’s important to note this is one measure and we can’t determine the risk of a heart attack or stroke from BMI.


How to stop obsessing over BMI:

Look beyond the scale

Using numbers like BMI and scale weight are just one type of measurement. For many people it can trigger an unhealthy emotional response or unhealthy behaviors like extreme restriction. Deciding to weigh yourself, or not, is an individualized choice. Also, if you are trying to improve your health, know that your BMI is not what is going to be the measure to tell you if you are making healthy behavior changes. It is important to use other factors outside of BMI to gauge how you feel and your health. Here are things beyond the scale you can consider and look at as a whole picture:

  • Energy level
  • Stress level
  • Sleep quality
  • Strength or flexibility
  • Bloodwork at your doctor’s office
  • Blood pressure
  • Relationship with food

If you are someone who likes seeing numbers and data you can even set specific goals such as walking 4 times a week and check off when you complete these goals.

Remember that BMI is not accurate and it’s normal for weight to go up and down 

The BMI calculation is an outdated metric that only applies to a population of white males with low muscle mass. A number of factors go into how much you weigh on any given day. With so much ambiguity and fluctuation around these numbers, it is best to not obsess over what they do or don’t say.

Talk to your doctor, Dietician, or therapist about your health

The most important thing you can do when it comes to your health is talk to your primary care physician, dietician, or mental health provider. Don’t let a misleading number lead you to thinking that you are healthy or unhealthy. Visit your doctor, get your blood work done, and see what a modern professional that is knowledgeable on your medical history has to say.

Your BMI is not your worth

We know the term obesity or overweight can send a shock through many people’s systems. Not only is BMI not a solid measure of health it is certainly not a measure of worth. You are not more worthy or valuable as a person if you are in the overweight category or normal weight category.


When to seek professional help:

If you feel like you could benefit from therapy related to body image, weight concerns, or any other concerns, do not hesitate to schedule a free consultation with one of our licensed psychologists at The psychologists at the practice all specialize in eating disorders, body image, health behavior change, and helping improve your relationship with food.


Thank you to Best Within You Therapy & Wellness Intern, Rumi Petvora