A New England Journal of Medicine study, published Monday, finds that more than 2 billion people – or one-third of the world's population – fall into the obese-or-overweight categories, CNN reports. What's more: Their weight is causing them to endure health problems.
The New York Times reports the per capita death rate has ticked up 28 percent since 1990, and40 percent of these deaths occurred among overweight people not heavy enough to be obese. In 2015, extra weight was a factor in 4 million deaths from conditions such as heart disease and diabetes.
More than 710 million people are considered obese, which translates to 10 percent of the global population.
For the purposes of the study, being obese meant having a body mass index of 30 or higher, while being overweight was defined as having a BMI between 25 and 29. The Institute for Health Metrics and Evaluation at the University of Washington led the Gates Foundation-backed study.
The U.S. earned the dubious distinction of having the highest percentage of obese children and young adults relative to the overall population (13 percent), while Egypt had the highest percentage of obese adults, with nearly 35 percent.
Looking beyond percentages at the actual numbers: The U.S. was home to the most obese adults (79.4 million), and China was home to the most obese children (15.3 million).
These findings are unsettling to experts, who worry about the health consequences of the world's expanding waistline. "People who shrug off weight gain do so at their own risk – risk of cardiovascular disease, diabetes, cancer, and other life-threatening conditions," Dr. Christopher Murray, study author and director of the Institute for Health Metrics and Evaluation at the University of Washington, told CNN.
Researchers used data from the Global Burden of Disease study in their analysis, which included 68.5 million people tracked between 1980 and 2015. They reported that in 73 countries, the obese population had doubled since 1980. Women had higher obesity levels than men no matter the age group, a finding that echoes previous research.
So, what comes next?
"We need to control the consequences of obesity much better globally ... and help people who are obese to lose weight," Goodarz Danaei, a professor at the Harvard T.H. Chan School of Public Health who didn't work on the study, told CNN. "That's where we need research and public health interventions."
But such interventions could prove complicated, particularly when it comes to increasing access to healthy food. "Unhealthy foods cost less; healthier foods often cost more. People eat what they can afford," Adam Drewnowsk, director of the Center for Public Health Nutrition at the University of Washington, told The New York Times. He also didn't work on the study.
It remains unclear what rising obesity rates mean for children. "We don't really know what the long-term effects will be if exposed to high BMI over 20, 30, 40 years," Danaei told CNN. "It may be larger than we have already seen."