How BMI Affects Health

Body mass index may incorrectly label millions of Americans as unhealthy

/ Author:  / Reviewed by: Beth Bolt, RPh

(RxWiki News) Body mass index (BMI) has recently become a way to gauge people's health in America. But new evidence suggests there may be a better way.

A new study from the University of California at Los Angeles (UCLA) found that a high BMI may not necessarily mean a person is unhealthy.

"Many people see obesity as a death sentence," said lead study author A. Janet Tomiyama, PhD, in a press release. "But the data shows there are tens of millions of people who are overweight and obese and are perfectly healthy."

Dr. Tomiyama is the director of UCLA's Dieting, Stress and Health laboratory.

BMI is a ratio of height to weight used to determine body fat percentage. A person whose BMI falls between 18.5 and 24.9 is considered of normal weight. Between 25 and 29.9 is considered overweight. Anything above 30 is considered obese.

According to Dr. Tomiyama and colleagues, BMI is increasingly being used by companies to make decisions related to workers' health care costs and insurance premiums.

The US Equal Employment Opportunity Commission (EEOC) recently proposed that employers could penalize employees for health insurance costs. Those who failed to reach certain criteria like achieving a "normal" BMI could pay up to 30 percent of their health insurance costs.

To investigate whether BMI is actually a good measure of a person's health, Dr. Tomiyama and team looked at more than 40,000 people who completed the most recent National Health and Nutrition Examination Survey (NHANES). They studied the link between BMI and health markers like blood pressure, blood sugar and cholesterol levels.

The results showed that nearly 48 percent of "overweight" Americans are actually healthy. An additional 19.8 million "obese" Americans are also healthy. By contrast, more than 30 percent of Americans — about 20.7 million people — whose weight was in the "normal" range were actually unhealthy.

According to Dr. Tomiyama and team, overweight and obese patients won't necessarily incur higher medical expenses, and it would be unfair to charge them higher health care premiums.

"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," Dr. Tomiyama said. "Employers, policy makers and insurance companies should focus on actual health markers."

This study was published Feb. 4 in the International Journal of Obesity.

No funding sources or conflicts of interest were disclosed.

Reviewed by: 
Review Date: 
February 7, 2016
Last Updated:
February 9, 2016