The Body Mass Index — a number, calculated from your height and weight, used by doctors to identify potential weight problems — is a flawed screening tool. Numerous studies have pointed to its limitations in the past, but an investigation published in PLoS ONE this April suggests that the use of BMI by physicians to assess "body fatness" (that's the CDC's term, not ours) has given rise to a gilded view of America's already troubling obesity epidemic.
By comparing the BMIs of 1,400 people against more accurate, X-ray measurements of their body fat, the researchers found that BMI correctly predicted obesity just three-fifths of the time, and that women were especially prone to misdiagnosis. According to Discover Magazine, the researchers propose addressing misdiagnoses by "changing the BMI obesity threshold (now at 30) to 24 for women, 28 for men. They also advise people to consider a body fat scan and a blood test for the hunger-suppressing hormone leptin."
"Shifting those currently considered overweight into the obese category would clarify the magnitude of the issue of obesity," write the researchers — albeit with staggering results. "By our cutoffs," they note, "64.1% or about 99.8 million American women are obese."