Why body weight isn’t an indicator of health

BMI is a poor measurement for health and mortality

When you think of body weight and standards of health, you probably think of body mass index (BMI). It’s used in many settings, from places of employment and schools to physician’s offices and personal training gyms. It’s been used as a measurement of healthy weight for over one hundred years.

And yet, it is extremely inaccurate, not to mention harmful and irresponsible. The only thing that BMI takes into account is your weight-to-height ratio. That’s it. It doesn’t consider any other influences, such as bone density, muscle mass, environmental and biological influences, sex and racial differences, and more. For example, an athlete may have high bone density and muscle mass, which may push their BMI into the “obese” range. 

"Thinner" bodies aren’t necessarily healthy

As much as the media and diet culture will tell you otherwise, thinner bodies are not necessarily healthy bodies. People can fall into the “healthy weight” category of BMI and have significant health problems. However, that’s not how our culture treats thinner people. The prevailing assumption in our society is that thinner bodies are healthier than higher-weight bodies. 

Historically, those who support BMI claim a BMI in the “overweight” or “obese” range increases a person’s risk for health complications and premature death. However, research indicates that being overweight is often associated with a lower mortality rate. (1) Additionally, studies have shown that nearly 50% of U.S. adults who fall into the “overweight” category for BMI are healthy, according to measurements of blood pressure, triglyceride and cholesterol levels, and glucose levels. And these metabolic indicators are more accurate indicators of health. An additional 20 million people who fall into the “obese” range were also shown to be healthy. (2)

BMI was created for the white European man

Created in the 19th century by Adolphe Quetelet, BMI was initially intended to measure the “average” or “ideal” man—more specifically, the white, European man, since those were the people he gathered his data from. (3) Clearly, from the very beginning, BMI was racist and inaccurate, and should never have been used as an indicator of health in the first place. BMI being used as a measurement of healthy weight for anyone is problematic, since body composition, muscle mass, bone density, and fat distribution vary between sexes and races, and metabolic indicators more accurately signify health.

A major and important example of this disparity is that of Black women. They tend to be healthier at higher weights than white women—and not only at higher weights, but also larger waist circumferences as well. (4,5) 

Further research has revealed that middle-aged and older African-American women and men had lower visceral adipose tissue—the fat around the organs responsible for many serious health risks—than their white and Hispanic counterparts, despite similar waist circumference measurements and BMI. (6)

Despite these important findings, healthcare professionals still fail to take racial diversity into account when prescribing weight loss to patients, especially Black women. Instead, they tend to incorrectly attribute various symptoms or complaints to having a higher weight without doing a thorough assessment to determine what actually may be causing the signs and symptoms and often recommend losing weight. This advice is uninformed, stigmatizing, and an example of the weight bias that exists in the healthcare community. (7) This weight bias can lead to under-treatment, internalized fatphobia, mental health complications, shame, and weight gain.  (8,9,10)

Diet culture and healthism have been part of the problem

Healthism is a set of beliefs that values an idealized concept of health, the achievement of which, through culturally acceptable means and methods, is the most essential pursuit in life. And, health, as such, is a morally superior state of well-being. Healthism puts the responsibility of achieving optimal health on the individual. Healthism holds that health is solely within the individual’s power through lifestyle changes–such as what we eat and how much we engage in physical activity, instead of considering all the biopsychosocial factors and systemic issues that influence a person’s physical and mental health. These include culture, the media, disease, genetics, social status, oppression, discrimination, etc. (11) Additionally, this attitude often conflates health and thinness, which we now understand are not synonymous and that thinness is not an indicator of health.

Diet culture is guilty of this as well. From fitness social media influencers and calorie-counting apps to food marketing labels and magazines touting weight-loss regimens, we are constantly bombarded with messaging that we should want to lose weight and have a thin waist and that this will make us healthy (not to mention worthy of love and respect). 

And diet culture and healthism are steeped in fat phobia and weight stigma. This results in significant discrimination against people living in higher-weight bodies, often accusing them of being irresponsible, unhealthy, or lazy. This, in turn, leads to internalized fatphobia and weight stigma, shame, mental health conditions–such as anxiety, depression, and suicidal ideation, and weight gain. (8,9,10)

It is important to remember that despite what media messaging may try to sell us on, being thin is not a moral good, thin bodies are not the “ideal” bodies, being overweight is not immoral, and fat bodies are not bad bodies. And you certainly cannot tell how healthy someone is just by looking at them, nor should you try to.

How to measure health without body weight

Countless studies have shown that body weight is not an accurate predictor of overall health and wellbeing. However, there are many other ways to measure a person’s health, including:

• Blood sugar levels, which can indicate a diabetes risk
• Blood pressure, which can be an indicator of heart health
• Cholesterol levels, which also indicates heart health and can predict potential cardiovascular complications
• Number of hours slept, which can indicate if someone is at risk of complications like heart disease, hypertension, or diabetes 
• Amount of movement/exercise, which promotes overall wellness and health and reduces the risk of premature death
• Amount of vegetables and fruits consumed, which is essential for wellness
• Number of alcoholic drinks consumed, which can indicate if someone is at risk of developing various health problems related to excessive drinking
• Hydration, which is important to our overall health
• Smoking status, as smoking causes many health complications, including cancer, COPD, and heart disease

When taken alone, none of these measurements provides an accurate portrayal of your health, but together, they can create a comprehensive picture of your wellness. One way to measure many of these things is to get a yearly check-up and blood test with your doctor. Blood tests measure many different factors, such as cholesterol levels, liver and kidney function, number of red and white blood cells, electrolyte and fluid balance, and more.

If you are unable to afford regular appointments or don’t have health insurance, some of the factors are within your control, such as making sure to drink an appropriate amount of water and making sure to move every day, even if it’s just a walk with your family or friend. 

At the end of the day, all humans should be treated with respect and dignity, no matter who they are or what they look like. Equipping yourself with knowledge and debunking common misconceptions can help you to combat weight stigma in your daily life, as well as challenge your own biased thoughts and attitudes. If you'd like to learn more about our approach to treating eating disorders in every body size, reach out to the team at Within.