For a number of soldiers, the old drop-and-give-me-20 just isn't enough. Instead, they're resorting to quick surgery to pass the military's "fat test."

With the aid of a recently published study by researchers from the London School of Hygiene and Tropical Medicine, the BBC was able to construct an online calculator that lets users determine where they fall on the global fat scale.

A report published yesterday in the Public Library of Science's PLoS One journal (clever) suggests that the body mass index (BMI), the formula commonly used to determine whether an individual is of a healthy weight, may be underestimating obesity in almost 40 percent of cases.