Obesity Rate in United States Close to 60% Reports New Study
Almost 40% of Americans currently classified as overweight are in fact clinically obese, according to a new study casting doubt on the body mass index (BMI), a formula from 1842 still commonly used to diagnose obesity today.
The US Centers for Disease Control and Prevention (CDC) classifies one in three Americans as obese, but Eric Braverman, MD, co-author of the study published on Apr. 2, 2012 in the peer-reviewed journal PloS One, says the true figure is closer to 60%, and that many people whose health is threatened by obesity-related conditions may not be receiving appropriate advice or treatment.
The obesity study (287 KB) , coauthored by Nirav R. Shah, MD, New York State Commissioner of Health, found that 48% of women and 25% of men classified as overweight by BMI were found to be obese when using a more accurate measure, the dual-energy x-ray absorptiometry (DXA) scan, which measures body fat.
BMI does not distinguish between fat and muscle. “Some people call it the ‘baloney mass index,'” says Braverman, explaining that bodybuilders can be deemed obese while people with dangerous amounts of body fat are underdiagnosed as merely overweight.
“BMI is about 75-percent accurate,” states Braverman. “No one in science is happy with something that’s wrong a quarter of the time – it just doesn’t add great value.” Lives are being lost to cancer, heart attacks, and strokes caused by “flab,” excess body fat that is unrecognized by BMI, says Braverman: “Flab is the key and flab is what kills. Flab will cost you 15 years of quality life.”
BMI, calculated by dividing a person’s weight by the square of his or her height (kg/m2), was developed in 1832 by Belgian mathematician, astronomer, and statistician Adolphe Quetelet, and gained popularity in the medical community because it was simple and inexpensive.
Using BMI as a measure, a July 2011 study by the Trust for America’s Health and the Robert Wood Johnson Foundation reported that obesity rates rose in 16 states over the past year. Mississippi has the highest obesity rate in the country at 34%, and Colorado has the lowest at 21%.
Some experts disagree with Braverman’s assertion that “this should be the beginning of the end for BMI.” Richard N. Bergman, PhD, Director of the Cedars-Sinai Obesity and Diabetes Research Institute, states that BMI has decades of research supporting it as a reliable indicator of risk from Type 2 diabetes, cardiovascular disease, and certain cancers. Links between DXA scan results and disease risk, however, have not been sufficiently established to warrant phasing out BMI altogether, says Bergman.
Lowering the threshold for obesity diagnoses, as the study suggests, could cause unintended problems, states James Hospedales, MD, Chief of Noncommunicable Diseases at the Pan American Health Organization. “We’d also be calling an increasing number of people obese who aren’t, which could lead to issues with stigma, insurance policies, and other problems,” says Hospedales. “We have to think quite carefully about the pros and cons.”
“‘Baloney Mass Index’ Putting Lives at Risk,” ABC (Australian Broadcasting Corporation) News website, Apr. 5, 2012
Melissa Healy, “We May Be Fatter Than We Think, Researchers Report,” LATimes.com, Apr. 2, 2012
Joyce Ho and Dr. Nancy Snyderman, “The Surprising New Face of Obesity,” MSNBC.MSN.com, Apr. 6, 2012
Jason Koebler, “Study: American Obesity Epidemic Much Worse Than CDC Believes,” ChicagoTribune.com, Apr. 3, 2012
Amanda MacMillan, “Obesity Rate May Be Worse Than We Think,” CNN.com, Apr. 3, 2012
Alice Park, “Americans May Be Fatter Than We Think, Study Says,” Healthland.Time.com, Apr. 3, 2012
Nirav R. Shah, MD, and Eric R. Braverman, MD, “Measuring Adiposity in Patients: The Utility of Body Mass Index (BMI), Percent Body Fat, and Leptin,” PLoSOne.org, Apr. 2, 2012
US Centers for Disease Control and Prevention (CDC), “Body Mass Index: Considerations for Practitioners,” CDC.gov (accessed Apr. 9, 2012)