The whole world is steadily becoming more obese, a new study shows, but not surprisingly, the U.S. is No. 1.
The survey of 188 countries shows that nearly 30 percent of the global population, or 2.1 billion people, are either overweight or obese. Not a single country has lowered its obesity rate since 1980, the first of its kind study shows.
And even though the United States accounts for just 5 percent of the world's total population, Americans make up 13 percent of the global overweight and obese population.
Perhaps most troubling, kids are heavier than ever, the survey by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington finds. The percentage of overweight or obese children and teenagers has increased by nearly 50 percent since 1980 and now more than 22 percent of girls and nearly 24 percent of boys in developed countries are overweight or obese.
"In the last three decades, not one country has achieved success in reducing obesity rates, 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," said Dr. Christopher Murray, director of the institute.
The survey finds that 160 million Americans are either obese or overweight. The U.S. has 78 million obese adults, the highest number of any country in the world, even China, with four times the population. Nearly three-quarters of American men and more than 60 percent of women are obese or overweight, it finds.
And nearly 30 percent of U.S. children and teens are either obese or overweight, up from 19 percent in 1980. That's nearly twice as many as in Europe. Just 4 percent of kids in the Netherlands or Sweden are overweight.
It's headed in the wrong direction, too — The Trust for America's Health projects that 44 percent of Americans will be obese by 2030, while the Centers for Disease Control and Prevention it projects 42 percent of adults will be. CDC also reported that 12 states have an adult obesity rate of over 30 percent.
Obesity is calculated using body mass index, a globally accepted ratio of height to weight. Someone who is 5 feet 5 inches tall and weighs 149 pounds has a BMI of 24, considered a healthy weight. Add a pound and the same person has a BMI of 25 and is considered overweight. At 170 pounds this person has a BMI of 40 and is considered obese.
The National Institutes of Health has a BMI calculator online here.
"Worldwide, the proportion of adults with a body-mass index (BMI) of 25 or greater increased between 1980 and 2013 from 28.8 percent to 36.9 percent in men, and from 29.8 percent to 38 percent in women," the researchers wrote in their report, published in the Lancet medical journal.
When people are too heavy, they have a much higher risk of heart disease, cancer, stroke, arthritis and a range of other ills.
One controversial study suggests obesity accounts for about 18 percent of all deaths in the United States.
The University of Washington team breaks down the obesity rates by age, also and finds 80 percent of men aged 50 to 54 are overweight or obese and 73 percent of women aged 60 to 64 are.
"Being overweight or even obese is a growing, unchecked problem in the U.S. today," said Dr. Ali Mokdad, Professor of Global Health at IHME. "We are looking at a major public health epidemic that must be stopped."
Dr. Derek Yach, executive director of the New York-based Vitality Institute, says the numbers are no surprise. And the explanation is simple.
"The overall message is people are increasingly getting out of energy balance," Yach, who was not involved in the research, told NBC News. "This is due to excessive intake, usually high in fat and sugar, and a dramatic decline in physical activity. In some parts of the world it is predominately and almost entirely an intake issue."
But what people are overeating varies from one part of the world to another, says Yach, an obesity expert who worked for PepsiCo for a while. In some places, such as South Africa, it's starchy food, says Yach, while in parts of Latin America it's snacks and sugary drinks.
And in countries like China, bike lanes have disappeared to be replaced by roads choked with traffic, Yach added.
One team tried to put a figure on how the increasing availability of fast food is affecting worldwide obesity rates.
The team of U.S. and Irish found that for every extra fast-food transaction in a country — every time someone bought a hamburger or a serving of fried chicken — the average BMI went up by 0.03.