Body mass index (BMI), which is calculated from height and weight, and its relationship to health is a hotly debated area of health. On the one hand, “it’s cheap, it’s intuitive, it’s noninvasive and easy to calculate,” Noa Rappaport told BioWorld. “But it misses a lot.” In the March 20, 2023, online issue of Nature Medicine, Rappaport’s group describes an alternative measure, which they have termed the biological BMI, that “better reflects metabolic health than traditional BMI,” said Rappaport, who is a senior research scientist at the Institute for Systems Biology and the paper’s corresponding author.