One in six U.S. adult deaths linked to excess weight

The mortality risk of being overweight is extremely higher than what was previously thought, according to a new study from CU Boulder. The experts report that obesity or excess weight increases the risk of death by 22 to 91 percent.

The results of the analysis, based on nearly 18,000 individuals, suggest that about one in six deaths in the United States 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 study author Professor Ryan Masters. “This study and others are beginning to expose the true toll of this public health crisis.”

The research contradicts the idea that only those who are classified as “extremely obese” have an increased risk of death. The current study shows that groups with higher BMIs have much higher mortality rates as well.

“The conventional wisdom is that elevated BMI generally does not raise mortality risk until you get to very high levels, and that there are actually some survival benefits to being overweight,” said Professor Masters. “I have been suspicious of these claims.”

Body mass index (BMI) is based on weight and height only and doesn’t account for differences in body composition or how long a person has been overweight, explained Professor Masters. He noted that Tom Cruise (at 5 feet 7 inches and an extremely muscular 201 pounds at one point), had a BMI of 31.5, putting him in the category of “obese.”

“It’s a reflection of stature at a point in time. That’s it,” said Professor Masters. “It isn’t fully capturing all of the nuances and different sizes and shapes the body comes in.”

The study was focused on data from the National Health and Nutrition Examination Survey (NHANES), which followed 17,784 people from 1988 to 2015.

According to the results of the analysis, there are no significant mortality risks associated with being “underweight.” In fact, individuals with low BMI (18.5–22.5) were found to have the lowest mortality risk.

On the other hand, the results suggest that U.S. adult deaths linked to high BMI are about eight times higher than previously estimated.

Professor Masters said he hopes the research will alert scientists to be “extremely cautious” when making conclusions based on BMI. 

“For groups born in the 1970s or 1980s who have lived their whole lives in this obesogenic environment, the prospects of healthy aging into older adulthood does not look good right now. I hope this work can influence higher-level discussions about what we as a society can do about it.”

The study is published in the journal Population Studies.

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By Chrissy Sexton, Earth.com Editor

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