Nearly 30 percent of the world’s population is either obese or overweight, according to a new study that also names the top 10 countries with the most obese people.

The study, published in the journal The Lancet, found that the number of overweight and obese people globally increased from 857 million in 1980 to 2.1 billion in 2013. Overweight is defined as having a Body Mass Index (BMI), or weight-to-height ratio, greater than or equal to 25 and lower than 30, while obesity is defined as having a BMI equal to or greater than 30.

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“Obesity is an issue affecting people of all ages and incomes, everywhere,” co-author Christopher Murray, director of the Institute for Health Metrics and Evaluation (IHME), said in a press release.

“In the last three decades, not one country has achieved success in reducing obesity rates,” Murray said, “and we expect obesity to rise steadily as incomes rise in low- and middle-income countries in particular, unless urgent steps are taken to address this public health crisis.”

The researchers are also concerned over the new data on children and adolescents. Between 1980 and 2013, the prevalence of overweight or obese children and adolescents increased by nearly 50 percent, according to the study. In 2013, more than 22 percent of girls and nearly 24 percent of boys living in developed countries were found to be overweight or obese.

“The rise in obesity among children is especially troubling in so many low- and middle-income countries,” said Marie Ng, assistant professor of global health at IHME and the paper’s lead author. “We know that there are severe downstream health effects from childhood obesity, including cardiovascular disease, diabetes and many cancers. We need to be thinking now about how to turn this trend around.”

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For the study, the researchers conducted what they say is a first-of-its-kind analysis of trend data from 188 countries. More than 50 percent of the world’s 671 million obese people live in just 10 of those countries:

  • United States

  • China

  • India

  • Russia

  • Brazil

  • Mexico

  • Egypt

  • Germany

  • Pakistan

  • Indonesia

The highest proportion of the world’s obese people, 13 percent, live in the United States. China and India together represent 15 percent of the world’s obese population. Rates in the study were age-standardized, meaning they were adjusted for differences in population size and ages over time and across countries.

Photo: Bill Branson, National Cancer Institute