Excess weight or obesity boosts risk of death by anywhere from 22% to 91%—significantly more than previously believed—while the mortality risk of being slightly underweight has likely been overestimated, according to new CU Boulder research.
The findings, published Feb. 9 in the journal Population Studies, counter prevailing wisdom that excess weight boosts mortality risk only in extreme cases.
The statistical analysis of nearly 18,000 people also shines a light on the pitfalls of using body mass index (BMI) to study health outcomes, providing evidence that the go-to metric can potentially bias findings. After accounting for those biases, it estimates that about 1 in 6 U.S. deaths are related to excess weight or obesity.
“Existing studies have likely underestimated the mortality consequences of living in a country where cheap, unhealthy food has grown increasingly accessible, and sedentary lifestyles have become the norm,” said author Ryan Masters, associate professor of sociology at CU Boulder.
“This study and others are beginning to expose the true toll of this public health crisis.”
Ryan Masters
Challenging the ‘obesity paradox’
While numerous studies show that heart disease, high blood pressure and diabetes (which are often associated with being overweight) elevate mortality risk, very few have shown that groups with higher BMIs have higher mortality rates.
Instead, in what some call the “obesity paradox,” most studies show a U-shaped curve: Those in the “overweight” category (BMI 25–
