Researchers from Huazhong University of Science and Technology and Hubei Medical University examined a growing pattern in the United States over two decades, focusing on those who carry a BMI in the obese range yet do not exhibit common health problems typically linked to excess weight. The finding appeared in a study published in JAMA Network Open, shedding light on how people can be classified as metabolically healthy despite obesity and what that means for public health messaging.
The core idea is straightforward: a subset of individuals with obesity do not present the usual metabolic complications such as high blood pressure, elevated fasting glucose, or abnormal cholesterol levels. This subgroup, often labeled metabolically healthy obesity, has been observed in multiple cohorts, and the current analysis adds to that understanding by tracking changes within a representative U.S. population over time. The researchers used data from NHANES, a continuous national survey conducted by the National Center for Health Statistics, to follow trends in obesity and metabolic health from the late 1990s through the late 2010s.
Across the study period, the share of the population classified as metabolically healthy obesity rose alongside the overall obesity rates. While those with metabolically healthy obesity still represent a relatively small fraction of all obese individuals, the increase signals shifting patterns in how obesity and metabolic risk are distributed across the population. The authors defined metabolically healthy obesity as having a body mass index (BMI) of at least 30 kg per square meter without hypertension, without high fasting glucose, and without elevated blood cholesterol. This operational definition helps researchers compare findings across studies and monitor how the category evolves with changing demographics and risk profiles.
In total, the analysis drew on NHANES data from around twenty thousand adults, of whom more than seven thousand met criteria for obesity. The data show that obesity became more prevalent in the United States, rising from about 28.6 percent to roughly 40.9 percent of the population over the study period. Within that larger group, the share of people considered metabolically healthy obesity climbed from about 3.2 percent to around 6.6 percent. The reporting emphasizes that while the absolute number grows, metabolically healthy obesity remains a minority among those who are classified as obese, and the implications for long-term health still require careful interpretation.
Researchers also caution that BMI alone may not capture the full picture of obesity or metabolic risk. BMI does not distinguish between muscle and fat mass or account for variations in bone density, which can lead to misclassification of metabolic health status for some individuals. In practice, clinicians are increasingly turning to additional measures to assess adiposity and risk. One widely discussed alternative is the waist-to-hip ratio, which can reflect abdominal fat distribution that correlates with metabolic risk. Such approaches aim to provide a more nuanced view of body composition and health outcomes beyond BMI, guiding more personalized risk assessment and intervention decisions. Attention to these newer metrics aligns with a broader shift in public health toward a more precise understanding of how obesity relates to cardiometabolic disease in diverse populations across the United States and Canada.