We’ll be the first to say that body mass index, which uses weight and height to measure body composition, is not exactly an ideal way to determine fitness and health. Richard Bergman, a University of Southern California professor of physiology and biophysics, agrees. According to surprising research he published in Obesity, hip circumference is the best indicator of percentage of body fat — better even than waist circumference. Bergman has translated this discovery into an equation, called the body adiposity index, that relates hips to height. And while it’s too soon to tell whether it will unseat BMI as mainstream medicine’s go-to diagnostic tool, it might just make us feel better about ourselves.