BMI and Life Expectancy

A comprehensive review published in 2013 in the 'Journal of the American Medical Association' examined the relationship of BMI (Body Mass Index) to death rates. The study researchers found that increasing levels of obesity were associated with progressively higher premature death rates.

Mildly obese people, however, did not have a significantly greater risk of death compared to those with a normal BMI. In fact, the finding that people classified as overweight but not obese had a lower overall death rate compared to those with a normal BMI. Researchers are exploring possible reasons for this finding.

The 'International Journal of Obesity' published a study in 2012 comparing BMI and waist circumference as predictors of life expectancy. The authors reported that waist circumference is a better predictor of death from any cause than BMI. The researchers also found that adults with a high waist circumference had an increased risk of death regardless of BMI. Although neither BMI nor waist size can accurately foretell the life expectancy of any individual, waist circumference may be a better tool for estimating longevity. In other words, they are saying 'we cannot accurately tell life expectancy with either of these measurements, but it does help get us grants and headlines'.