Obesity Classification in Military Personnel: A Comparison of Body Fat, Waist Circumference, and Body Mass Index Measurements

TLDR

The study aimed to evaluate obesity classifications using body fat percentage (BF%), body mass index (BMI), and waist circumference (WC). A cohort of 451 overweight/obese active‑duty military personnel completed all three assessments. Using BF% criteria, 81 % of men and 98 % of women were classified as obese, whereas BMI and WC identified only 55.5 %–51.4 % and 21.4 %–31.9 % of men and women, respectively, yet BMI/WC discriminated BF% obesity with θ > 0.75 and optimal cutoffs of 29 BMI/100 cm for men and 25.5–26 BMI/79–83 cm for women, indicating that although WC/BMI miss many individuals, they retain fair‑to‑high discriminatory power at the population level.

Abstract

Objective: The purpose of this study was to evaluate obesity classifications from body fat percentage (BF%), body mass index (BMI), and waist circumference (WC). Methods: A total of 451 overweight/obese active duty military personnel completed all three assessments. Results: Most were obese (men, 81%; women, 98%) using National Institutes of Health (NIH) BF% standards (men, >25%; women, >30%). Using the higher World Health Organization (WHO) BF >35% standard, 86% of women were obese. BMI (55.5% and 51.4%) and WC (21.4% and 31.9%) obesity rates were substantially lower for men and women, respectively (p < 0.05). BMI/WC were accurate discriminators for BF% obesity (θ for all comparisons >0.75, p < 0.001). Optimal cutoff points were lower than NIH/WHO standards; WC = 100 cm and BMI = 29 maximized sensitivity and specificity for men, and WC = 79 cm and BMI = 25.5 (NIH) or WC = 83 cm and BMI = 26 (WHO) maximized sensitivity and specificity for women. Conclusions: Both WC and BMI measures had high rates of false negatives compared to BF%. However, at a population level, WC/BMI are useful obesity measures, demonstrating fair-to-high discriminatory power.