BMI again proven to be useless

BMI again proven to be useless

Context: 20 years ago i applied for life insurance. At that time i did quite a bit of muscle building. I wasn’t a bodybuilder, but i had quite a lot of muscle and little fat. As a result my BMI was 32 due to muscles being heavier than fat. And got slapped with a 10% increase of premiums due to my BMI. I knew this was unjust. I wasn’t a couch potato. As much as i protested there was no arguing. I could take it or leave it. So i left it. Which made me research in depth the BMI phenomenon. Here is yet another installment proving how this system malfunctions

Approximately 75 million US adults may be misclassified as cardiometabolically healthy or unhealthy when using Body Mass Index (BMI) categories as the main indicator of health, reports research published in the International Journal of Obesity this week. The authors argue that policymakers should consider the unintended consequences of relying solely on BMI as a measure of health when determining policy.

New rules proposed by the US Equal Employment Opportunity Commission would allow employers to penalise employees up to 30% of health insurance costs if they fail to meet certain ‘health’ criteria, such as a specified BMI. However, this policy carries with it the assumption that a higher BMI uniformly indicates that individuals must be in poor health.

Using blood pressure, insulin resistance, C-reactive protein data and triglyceride, cholesterol and glucose counts from 40,402 nationally representative individuals aged over 18, A. Janet Tomiyama and colleagues compared cardiometabolic health (the risk of diabetes and heart disease) to BMI. The authors found that nearly half of overweight individuals, approximately 29% of obese individuals, and 16% of very obese individuals, as categorised by BMI, were cardiometabolically healthy. In contrast, over 30% of individuals whose BMI was considered ‘normal’ were found to be cardiometabolically unhealthy.

The authors suggest that while BMI may be seen as a quick, convenient and inexpensive marker for health, its use as an indicator may have detrimental consequences for the health and wellbeing of heavier individuals.

The study found that close to half of Americans who are considered “overweight” by virtue of their BMIs (47.4 percent, or 34.4 million people) are healthy, as are 19.8 million who are considered “obese.”


Given their health readings other than BMI, the people in both of those groups would be unlikely to incur higher medical expenses, and it would be unfair to charge them more for health care premiums, Tomiyama said.

Among the other findings:

  • More than 30 percent of those with BMIs in the “normal” range — about 20.7 million people — are actually unhealthy based on their other health data.
  • More than 2 million people who are considered “very obese” by virtue of having a BMI of 35 or higher are actually healthy. That’s about 15 percent of Americans who are classified as very obese.

Tomiyama, who directs UCLA’s Dieting, Stress and Health laboratory, also called DiSH, found in previous research that there was no clear connection between weight loss and health improvements related to hypertension, diabetes, and cholesterol and blood glucose levels.

She said she was surprised at the magnitude of the numbers in the latest study.

“There are healthy people who could be penalized based on a faulty health measure, while the unhealthy people of normal weight will fly under the radar and won’t get charged more for their health insurance,” she said. “Employers, policy makers and insurance companies should focus on actual health markers.”

Jeffrey Hunger, a co-author of the paper and a doctoral candidate at UC Santa Barbara, said the research shows that BMI is a deeply flawed measure of health. “This should be the final nail in the coffin for BMI,” he said.


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