BMI standards don’t correlate with fatness equally for different people. At the same BMI, those assigned female at birth tend to have more body fat than those assigned male at birth; older people have more than younger people; and athletes have less than nonathletes. People of Asian descent tend to have more body fat than white people at the same BMI; yet, for Black people, the opposite is true.

Indeed, about 75 million adults in the United States are being misclassified as healthy or unhealthy based on their BMI alone, one study suggests. In that study group, 48 percent of the participants in the overweight category (BMI 25–29.9) were actually healthy, according to measures such as blood pressure, blood sugar, and cholesterol. So were 29 percent of people with BMIs between 30 and 34.9, and 16 percent of those with BMIs of 35 and above. Meanwhile, 31 percent of people deemed to be at a healthy weight by BMI standards were categorized as unhealthy using other medical tests. The Best Natural Pills To Burn Fat Because BMI is frequently used to determine medical care and life insurance rates, these misclassifications can be meaningful.

Further, current standards may lead Black people to be disproportionately miscategorized as having obesity and a higher risk of death. For Asians, the opposite happens, with their risk of metabolic and heart diseases more likely to be overlooked.