National Eating Disorders Association

Changing the Way We Measure Health

Michelle Zaydlin

The modern-day term ‘body mass index (BMI)’ was first established in a medical paper published in 1972, as a “relative weight index of general obesity. ” Since then, healthcare professionals have used it as a tool to categorize individuals as underweight, normal weight, overweight or obese based on the amount of tissue mass (muscle, fat and bone) the individual possesses. 

Recently, many groups and individuals have been fighting against the use of BMI as a screening tool, particularly as it has become more commonly used in the school system.

Healthcare professionals, along with advocacy groups and individuals, have been analyzing the use of BMI both in the medical and school setting in an attempt to change the way we talk about BMI.  

School-based BMI measurement programs have begun sending “report cards” home with children. These report cards indicate the child’s BMI and weight category: underweight, normal weight, overweight or obese. Currently, there are 19 states that implement this type of program.

The National Eating Disorders Association (NEDA) has concerns about BMI report cards, because BMI screenings, such as the ones done in schools, may be triggering for individuals who are struggling with or vulnerable to eating disorders. The fear is that if an individual is already struggling with an eating disorder, being evaluated in this way may serve as a trigger for continued or worsening disordered behavior.

While a BMI screening alone cannot cause an eating disorder—as these are complex, multifactorial disorders—individuals who are at an increased risk for an eating disorder may be triggered through receipt of a BMI report card. NEDA has taken a stand against these screenings, encouraging schools and individuals to focus on health and not weight or BMI.

Many parents are against the use of BMI report cards and have gone public with their opinion that receiving a number on a report card does not positively impact a child. They feel that working with physicians and other health care providers is significantly more beneficial in maintaining their child’s heath than receiving a report card with just a BMI value, and no information regarding overall health or mechanisms by which to improve health.

Many parents also fear the effect of BMI report cards on their children’s physical and emotional health, as well as the potential for these reports to increase rates of bullying in schools. Overall, many parents dislike the use of these BMI reports, in particular from schools, and hope to discontinue this practice.

Several healthcare professionals are also fighting against the use of BMI in patients. A study conducted by Margaret Ashwell examined the relationship between BMI and health outcomes in 300,000 patients; this study found that BMI was a poor predictor of risk for diseases such as diabetes, hypertension and stroke. Studies such have established BMI as a poor measurement tool for determining patient health and for predicting future health outcomes. Instead, professionals have begun to recommend other forms of height to weight ratios that account for patient body type and lifestyle, which BMI does not.

Physicians at the Center for Weight and Wellness go on to point out several drawbacks to BMI—in particular, the fact that BMI does not take into account an individual’s body type and makeup, which makes BMI a misleading measurement tool. The Center for Weight and Wellness emphasizes that BMI does not consider muscle mass, activity level, body type, age or ethnicity, all of which play a role in determining what a healthy weight is for that particular individual. Physicians at the clinic also recommend using alternative measures to BMI.

Finally, BBC news looked at many opinions regarding the use of BMI and, based on this, strongly emphasize that BMI serves only as a measure of weight relative to height. It is clear that while BMI may be an effective tool for looking at population trends and for screening, it is not an accurate diagnostic tool on an individual patient level. They explain that BMI is simply a categorization of weight and not of health. They emphasize utilizing alternative measures of health, instead of focusing on BMI and allowing yet another number to define an individual.

Overall, it is evident that controversy exists about the use of BMI—in particular, its use in schools and within the healthcare field. The current consensus seems to be that BMI has many faults and is not always an accurate categorization.

On top of that, BMI presents risks for increasing rates of bullying within schools, and may serve as a trigger for individuals at risk for or struggling with eating disorders. Moreover, it is evident that focusing on yet another number provides limited value, and that what is most important is placing emphasis on overall physical and emotional health and wellness. 

This piece was originally published on, NEDA's website for teens and young adults. 

Image courtesy of Southern Smash