Validity of percent body fat predicted from circumferences: classification of men for weight control regulations

Each of the military services classifies individuals in their weight control programs using percent body fat predicted by circumference-based equations. Although derived independently from service-specific samples, each of the male equations relies on waist circumference adjusted by a neck circumference. In this study, the authors examined the performance of the equations in 496 young (< 40 years) male soldiers, compared to percent body fat measured by dual-energy X-ray absorptiometry. The strength of the relationship to percent body fat improved from body mass index (weight/height2), to a waist circumference alone, to the difference between waist and neck circumferences. Overweight men who were misclassified by overestimation of total percent body fat using the equations (2.6% of the total sample) had normal neck circumferences and height but large waistlines, indicating that they were still classified appropriately to the goals of the weight control programs, all of which center on abdominal adiposity. The authors demonstrate that each of the service equations yield substantially similar results and discuss why a single equation could be easily agreed to and used by the Department of Defense for male body fat prediction.