Revisiting the obesity paradox: visceral fat distribution outperforms BMI in predicting mortality and cardiometabolic risk

Background: The obesity paradox – where overweight and mild obesity appear associated with improved survival in some cardiometabolic conditions – challenges clinical risk stratification. The inability of body mass index (BMI) to discriminate lean mass from fat, or visceral from subcutaneous adipose tissue, may underlie this paradox. Methods: To evaluate whether direct measures of abdominal fat distribution and metabolic health status more strongly associate with cardiometabolic morbidity and mortality than BMI alone, and whether they clarify the observed obesity paradox. This cross-sectional analysis with prospective mortality follow-up included 15 925 adults from the 2011–2018 U.S. National Health and Nutrition Examination Survey (NHANES), a nationally representative cohort. Data analysis was performed from July 2025 to October 2025. Results: Among 15 925 participants, higher VFI and VFI/SFI ratio were consistently associated with increased mortality, whereas higher SFI was protective. After full adjustment, the highest quartile of VFI was associated with significantly increased risk of all-cause [hazard ratio (HR), 1.67; 95% CI, 1.19–2.33] and cardiometabolic mortality (HR, 2.92; 95% CI, 1.44–5.93). The VFI/SFI ratio showed similarly strong associations (all-cause mortality HR, 1.75; 95% CI, 1.19–2.58; cardiometabolic mortality HR, 2.90; 95% CI, 1.42–5.90). In contrast, overweight and obesity class I showed a lower risk of all-cause mortality compared to normal weight (overweight HR, 0.74; 95% CI, 0.56–0.99). Fat distribution indices demonstrated a strong association with CMD incidence in older adult (≥45 years). Metabolically unhealthy status was also a significant mortality risk factor, particularly in females. Conclusions: In this cross-sectional study of U.S. adults, visceral fat accumulation and an unfavorable fat distribution ratio were more strongly associated with mortality and CMD risk than BMI alone. The apparent survival advantage of elevated BMI was attenuated after accounting for fat distribution and metabolic health. These findings suggest that clinical assessment of obesity-related risk should incorporate measures of fat distribution and metabolic phenotype beyond BMI.