Objective: VAT volume is a critical determinant of cardiometabolic risk, yet population-specific thresholds and accessible predictive tools remain undefined. Methods: Using US National Health and Nutrition Examination Survey (NHANES) data, we analyzed dual-energy x-ray absorptiometry (DXA)-derived VAT volume. Threshold effects and sex/ethnicity interactions were evaluated via multivariable regression, while LASSO regularization and ROC analyses identified a simplified predictive model. Results: A VAT volume threshold of 327.0 cm3 stratified CVD risk, distinguishing compensatory from pathological adiposity. The high-VAT group exhibited elevated CVD prevalence (2.41% vs. 1.12%, p = 0.016), metabolic dysregulation, and socioeconomic disparities. Males showed higher risk thresholds than females (387.5 vs. 312.0 cm3, p-interaction = 0.029). Non-Hispanic White participants and multiracial groups exhibited abrupt risk escalation above 399.5 and 270.0 cm3 (aOR = 1.08–1.12, p < 0.001), absent in non-Hispanic Black individuals and Hispanic individuals. A tri-biomarker model (waist circumference + triglycerides + apolipoprotein B) achieved near-equivalent accuracy to DXA-based VAT quantification (AUC = 0.821 vs. 0.819, p = 0.66), with high sensitivity (80.95% vs. 69.05%) and cost-effectiveness. Conclusions: This study establishes the first sex-specific and ethnicity-specific VAT thresholds for CVD risk stratification and provides a clinically actionable tool for visceral adiposity screening.