Think your BMI is healthy? Your waist may say otherwise

For years, body mass index (BMI) has been used as a simple way to gauge obesity and the associated health risks. However, a recent study published in the Journal of the American College of Cardiology suggests that BMI may not provide the full picture of an individual's cardiovascular risk. Researchers found that among people classified as normal weight or overweight by BMI, those with a higher waist circumference or waist-to-hip ratio had a significantly higher risk for various cardiovascular issues, such as heart attack, stroke, heart failure, and atrial fibrillation.

The study, which analyzed data from 15 long-term prospective cohort studies involving over 259,000 individuals, revealed that BMI fails to account for the distribution of body fat, particularly abdominal fat. Unlike visceral fat, which surrounds internal organs and has a significant impact on metabolism and inflammation, BMI is a measure of weight relative to height and does not differentiate between fat and muscle or reveal where fat is concentrated.

As a result, a muscular person may appear to have a high BMI due to excess muscle mass, despite having low body fat. Conversely, some individuals with high levels of abdominal fat may have a normal BMI, misleadingly suggesting a lower risk for cardiovascular disease. The researchers emphasize that waist circumference, although not a direct measure of visceral fat, serves as a useful indicator of excess abdominal fat.

Medical guidelines already acknowledge the importance of considering central obesity when assessing cardiovascular risk, and the latest guidelines place even greater emphasis on incorporating measures of body composition and central obesity alongside BMI.