Last week, a study published in the International Journal of Obesity found that the body mass index did not fare well as an overall predictor of metabolic health.

The study, conducted by researchers at the University of California, Los Angeles and University of California, Santa Barbara, recorded the metabolic analyses of over 40,000 people.

The researchers found that 29 percent of those labeled as obese and 16 percent of those labeled as morbidly obese were incorrectly led to believe they were metabolically unhealthy. Additionally, 30 percent of participants with a normal weight were found to be metabolically unhealthy.

This finding now questions the impact that BMI has on people who receive health insurance from their employers.

In the study, the researchers said the Equal Employment Opportunity Commission has recently proposed rules that would allow for a company to charge its employees 30 percent more for their health insurance if they fail to fall within the accepted BMI range of 18 to 24.99. 

The data gathered now leads researchers to question whether this practice should be continued.

“The BMI has been used extensively for many years because it is the quickest and dirtiest measure we have on estimating body composition,” said Douglas Keen, a senior lecturer in the UA physiology department. “The problem with BMI, however, is that it does not take into account the difference between lean body mass and fat.”

Scott Going, head of the UA nutritional sciences department, gave his opinion on the use of BMI when it comes to the overall health of an individual.

“Because the BMI provides no information about tissue composition, it is very important to also consider other methods of measuring metabolic health,” Going said. “In conjunction with the BMI, employers should require the use of calipers or bioelectrical impedance devices. These provide a more accurate representation of metabolic health.”

Calipers are tools that measure the distance between two objects. Calipers can be used to measure thickness of skin folds in certain parts of the body and provide an estimate of body fat from that. 

Going said there are studies that have indicated a correlation between the thickness of skin folds measured and the risk of metabolic disease, such as Type 2 diabetes.

The new research suggests that BMI is not a fool-proof way to determine health or a healthy body weight. Some encourage the abandonment of the method all together.

If the BMI is proven to be inaccurate for measuring metabolic health, there are other methods that could be relied on instead.

Keen said newer body weight scales at home can estimate body fat and do so through bioelectrical impedance, providing a much better indication of overall health than BMI. When asked whether the medical field should do away with the use of BMI, Keen felt that the method does still prove to be useful for some individuals.

“For the general population, the BMI has worked very well as a rough estimate for metabolic health,” Keen said. “When you get into extreme cases, however, especially those of very muscular athletes, the BMI should be used in conjunction with other methods to ensure accuracy in your results.”

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