BMI May Misclassify One in Three Adults, Study Finds

New research from Italian scientists suggests that the commonly used Body Mass Index (BMI) may inaccurately classify a significant portion of adults. The findings, to be presented at the European Congress on Obesity 2026 and published in Nutrients, indicate that BMI often fails to reflect true body fat levels.

Using Dual-energy X-ray absorptiometry (DXA), considered the gold standard for measuring body composition, researchers reassessed 1,351 adults. They found that over one-third were placed in incorrect weight categories by BMI.

Misclassification was especially high among those labelled overweight or underweight. For instance, more than half of individuals classified as overweight by BMI were reassigned to different categories when body fat percentage was considered.

Experts say BMI’s limitation lies in its inability to measure fat distribution or distinguish between fat and muscle. The study highlights the need to combine BMI with more accurate tools to improve health assessments and public guidelines.

03-04-2026