Healthcare providers often look at patients’ body mass index (BMI) as an indicator of health and potential risks. We’re told that “normal” BMI is between 18.5 and 25, and anything outside this range is classified as underweight, overweight, or obese. However, these measurements are broad generalizations that were meant to reflect observations of large populations, not guide individual health advice. Because BMI uses no information other than a person’s height and weight, it provides no insight into the amount of fat an individual carries or how that fat might impact their health.