Why Use BMI as Measure of Health?

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There has been a new study showing that 54 million Americans whose BMI classed them as overweight and obese are actually in perfect health according to cardiometabolic measures. Another 21 million whose BMI places them in the normal category are unhealthy. BMI is a person’s body mass index that equals weight in kg divided by height in m2 and is a flawed measure of health. It is and has been a yardstick for determining health status and many employers use it to calculate workers’ health care costs. Equal Employment Opportunity Commission (EEOC) is proposing a rule, and if adopted, employers will be allowed to charge employees up to 30% of health care costs if they fail to meet certain health criteria such as not having a BMI in the normal range between 18.5 and 24.99. Now what sense would that make if the study has proven that many in the normal category are unhealthy and many in the overweight category are healthy? Think of the consequences to those individuals in affording their health insurance.

Janet Tomiyama, an assistant professor of psychology at the University of California analyzed the link between BMI and cardiometabolic health using data from the most recent National Health and Nutrition Examination Survey (NHANES). The cardiometabolic health data in the NHANES gives measure of blood pressure, triglycerides, cholesterol, glucose, insulin resistance and C-reaction protein (a marker of inflammation). BMI misclassifies nearly 75 million Americans as healthy or unhealthy. Does this seem a reasonable way of assessing healthy human beings to you?

The researchers found that 15% of Americans (2 million people) whose BMI calculation is 35 or higher, placing them as very obese, are actually healthy. Prof. Tomiyama says that these people would be unlikely to incur higher medical expenses and it would be unfair to charge them higher premiums based on only their BMI. They also revealed that 30% of Americans whose BMI is in the normal range (nearly 21 million) are actually the unhealthy ones according to cardiometabolic measures. It’s just completely unfair for healthy people to be penalized while unhealthy people will not get charged more, based just on the BMI. Employers, policy makers and insurance companies should focus on actual health markers such as stress, blood pressure, diabetes, cholesterol, glucose and other measures.

Co-author Jeffrey Hunger, a doctoral candidate at the University of California, urges people to obsess less about their weight and focus on following a healthy diet, which includes regular exercise. This information should confirm how flawed BMI is as an indicator of health and that “this should be the final nail in the coffin for BMI”. This is absolutely an inaccurate measure of body fat content and there should be more accurate, practical and affordable tools to measure biomarkers that can better predict the risks of disease and death. Don’t let your BMI be your deciding factor on obesity and health!

–Dr Fredda Branyon