Study Reveals Hidden Obesity Among Those With Normal BMI

A new study highlights a concerning health trend: many individuals classified as having a “normal” body mass index (BMI) may actually be experiencing obesity, which poses higher risks for various health complications. Researchers from a large international team analyzed survey data from the World Health Organization (WHO) and discovered that approximately one in five people worldwide with a healthy BMI exhibit signs of abdominal obesity.

The findings, published in JAMA Network Open this month, indicate that these individuals, often termed “skinny-fat,” have an increased likelihood of developing conditions such as high blood pressure and high cholesterol. The researchers emphasize that solely relying on BMI could lead to significant health issues being overlooked by medical professionals.

BMI is traditionally calculated based on a person’s weight and height, with obesity defined as a BMI of 30 or higher. Recently, healthcare experts, including those affiliated with the American Heart Association, have advocated for a broader understanding of obesity. In January, a coalition of specialists proposed that doctors should consider additional measurements, such as waist circumference, alongside BMI to better assess an individual’s health.

Research Insights from Global Survey

The study utilized data from the WHO STEPS survey, a comprehensive project aimed at tracking noncommunicable disease risk factors among populations. The analysis included nearly half a million participants from 91 countries over a two-decade span, from 2000 to 2020. About 21% of respondents were identified as having “normal-weight abdominal obesity,” meaning they maintained a healthy BMI while also possessing a waist measurement indicative of obesity.

Compared to those with both a normal BMI and waistline, individuals within this group displayed a higher prevalence of hypertension, high cholesterol, and diabetes. This underscores the need for more nuanced obesity assessments that go beyond BMI alone.

The significance of these findings aligns with previous research indicating a shift in obesity definitions. A study released earlier this month revealed that nearly 70% of Americans now meet the updated criteria for obesity, which includes 25% of individuals classified with normal BMI but who exhibit other indicators of excess body fat, such as waist circumference. These findings suggest that those categorized as “skinny” may still be at an elevated risk for health issues.

Recommendations for Comprehensive Health Assessments

The authors of this latest research assert that their study is the first to thoroughly evaluate the global prevalence of this hidden form of obesity. Instead of dismissing BMI altogether, the researchers advocate for its use in conjunction with additional measurements to offer a more complete picture of cardiovascular and metabolic health.

“Our findings suggest the need to use both BMI and waist circumference together, rather than in isolation, to provide a more complete and accurate assessment of cardiometabolic risk across diverse populations,” the researchers stated.

These results serve as a critical reminder for individuals to seek comprehensive health evaluations during routine medical checkups. Doctors should go beyond merely assessing BMI to ensure that potential health risks associated with hidden obesity are adequately addressed.