A new study challenges the belief that being overweight, as determined by the body mass index (BMI) scale, is associated with a higher risk of death.

The BMI scale calculates body fat based on height and weight, categorizing adults as "overweight" if their BMI falls between 25 and 29.9. A BMI of 30 or higher is considered obese, according to the Centers for Disease Control and Prevention (CDC).

However, the new study suggested that using BMI alone as an indicator of mortality risk is inadequate and should be complemented with additional measures such as waist circumference and weight trajectory.

The research published in the journal PLOS ONE, conducted by Dr. Aayush Visaria and Dr. Soko Setoguchi from Rutgers Robert Wood Johnson Medical School, analyzed data from over 554,000 non-pregnant Americans aged 20 and older.

The participants' BMI levels were compared with death rates over a 20-year period. The findings indicated that while there was a modest increase in mortality risk for individuals with BMI levels higher than 27.5, there was no significant increase in mortality for adults aged 65 and above with a BMI between 22.5 and 34.9.

However, experts not involved in the study said via CNN that the findings should be interpreted with caution due to certain limitations. They pointed out that observational studies can only establish associations, not causation.

Furthermore, the study did not consider other important outcomes, such as quality of life or the development of comorbidities like diabetes or heart disease. It is also worth noting that unintentional weight loss due to illness among older individuals may have influenced the U-shaped curve relationship between BMI and mortality.

The study emphasized the need to consider broader health measures beyond BMI alone. Waist circumference and other measures of adiposity were found to be more informative in predicting mortality risk.

Elevated waist circumference was associated with higher mortality risk, particularly in the overweight BMI range. Deep abdominal fat, known as visceral fat, has been linked to various health complications such as dementia, heart disease, frailty and premature death.

While the study highlighted the limitations of using BMI as the sole indicator of health risk, experts stressed that excess weight still poses risks and can lead to multiple health conditions. The American Medical Association and the American Heart Association recommend incorporating additional measures such as waist circumference alongside BMI for a comprehensive health assessment.

Ultimately, a holistic approach that considers various factors, including fat distribution and overall health, is crucial for understanding an individual's health risks associated with weight.