It's called the body adiposity index, or BAI.
It's meant to offer a flexible alternative to body mass index, or BMI.
BMI is a ratio of height and weight. But researchers reporting in the journal Obesity say there is too much wiggle room in that calculation.
BAI is a complex ratio of hip circumference to height that can be calculated by doctors or nurses with a computer or calculator.
Authors say BAI still needs some fine tuning but they think it has great promise.