Cohorts Create Action: Why How We Define Obesity Matters

We have discussed why including waist circumference is valuable in creating definitions of obesity for better PROACTIVE CARE strategy and better health outcomes for members, not to create cliques or judgment, but to define cohorts who carry increased risk for morbidity and mortality due to higher amounts of adipose tissue. In medicine, we create cohorts to create action, diagnosing appropriately so we can treat appropriately and attribute limited healthcare resources to those who most need them. What the popular press is now signaling to benefits leaders is that rising medical and pharmacy costs are not going away without a unified, holistic obesity strategy, because obesity sits upstream of nearly all top high-cost medical categories year after year, driving higher risk, higher utilization, and higher per-treatment cost as the market responds with increasingly expensive technologies. These quarterly cost increases have origins, many of which are preventable, and rising obesity is among the greatest; proactively identifying and addressing it is our only way out and can be a win for all stakeholders, a point underscored by research showing that when waist-based measures are included alongside BMI, more than 75% of U.S. adults may meet criteria for obesity and nearly four in ten adults with a “normal” BMI have excess body fat, reinforcing the urgency of earlier, more precise identification and intervention (Al-Roub et al., 2025).

Al-Roub, N. M., Malik, D., Essa, M., et al. (2025). Body mass index and anthropometric criteria to assess obesity. JAMA Network Open, 8(12), e2549124. https://doi.org/10.1001/jamanetworkopen.2025.49124