The USA leads the world in obesity, but it's far from the only country with a weight problem. (Photo: Mark Lennihan, AP) 
 
 By sheer numbers, the USA handily leads the world in obesity, with 87 million of the world's 671 million obese people — 13% of the total for a country with 5% of the population, a new report says. 
 
 But we are hardly alone in our battle with bulges: Obesity is a growing problem worldwide and, by proportion, is even worse in some other countries, says the study to be published Thursday in the medical journal Lancet. Rates are rising among men, women and children, in rich countries and in poor countries, the report says. 
 
 "It's going up everywhere," says study co-author Christopher Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington-Seattle. 
 
 The new 188-country study is the most comprehensive look at obesity worldwide over the past several decades, and it paints a discouraging picture, Murray says: "The most concerning thing is that there's not a single country that has seen a decline in obesity in the past thirty years. … We hoped there would be some examples of success that you could latch onto. But there's a complete lack of success stories in bringing down obesity." 
 
 Obesity is more common in developed countries than in poorer nations, but it is rising in both, the report says. Throughout the world – including in the USA – obesity co-exists with pockets of hunger, Murray says. 
 
 Among the details: 
 
 •The number of overweight or obese individuals worldwide increased from 857 million in 1980 to 2.1 billion in 2013. That's nearly 30% of the world's population, up from about 20%. 
 
 •About one-third of adults in the USA are overweight (with a body mass index of 25 or above), and another third are obese (with a body mass index of 30 or above), as has been reported by the Centers for Disease Control and Prevention. 
 
 •Obesity rates are even higher in some countries, exceeding 50% among men in Tonga and among women in Kuwait, Kiribati, Micronesia, Libya, Qatar, Samoa and Tonga. "Those are extraordinary levels," Murray says. 
 
 •About 22% of girls and 24% of boys in developed countries are overweight or obese. So are 13% of boys and girls in developing countries. 
 
 •In the USA and other developed countries, increases in obesity have slowed; in developing countries, rates are accelerating. 
 
 The new study does not examine causes but lists possibilities, including increased calorie intake, changes in diet composition, decreased physical activity and even changes in the mix of bacteria that live in human guts in the modern world. 
 
 The report notes that population-wide weight gains and income gains generally go hand in hand around the world. 
 
 That seems to support a theory, advanced by another recent study, that a major cause of obesity is that food has become cheap relative to income. 
 
 "It's not just cheaper in terms of money. It's also more accessible and more available all the time in the form of prepackaged junky food that is not necessarily conducive to health," says Roland Sturm, a senior economist at RAND and co-author of that study, published last week in CA: Cancer Journal for Clinicians. 
 
 "It's a good thing that hunger has decreased," Sturm says, "but now we have to deal with another health issue." 
 
 This month, the World Health Organization launched a commission to study rising obesity among children worldwide and suggest solutions. A report is due in early 2015. 
 
 Read or Share this story: http://www.usatoday.com/story/news/nation/2014/05/28/world-obesity-report/9675267/ ||||| Surgeon Dr. Alexandre Lesage examines an obese patient in his office prior to surgery at the Saint Jean d'Angely Hospital, in Saint Jean d'Angley, France in this file photo taken January 24, 2013. 
 
 WASHINGTON Obesity is imposing an increasingly heavy burden on the world's population in rich and poor nations alike, with almost 30 percent of people globally now either obese or overweight - a staggering 2.1 billion in all, researchers said on Wednesday. 
 
 The researchers conducted what they called the most comprehensive assessment to date of one of the pressing public health dilemmas of our time, using data covering 188 nations from 1980 to 2013. 
 
 Nations in the Middle East and North Africa, Central America and the Pacific and Caribbean islands reached staggeringly high obesity rates, the team at the University of Washington's Institute for Health Metrics and Evaluation in Seattle reported in the Lancet medical journal. 
 
 The biggest obesity rises among women came in Egypt, Saudi Arabia, Oman, Honduras and Bahrain. Among men, it was in New Zealand, Bahrain, Kuwait, Saudi Arabia and the United States. 
 
 The richest country, the United States, was home to the biggest chunk of the planet's obese population - 13 percent - even though it claims less than 5 percent of its people. 
 
 Obesity is a complex problem fueled by the availability of cheap, fatty, sugary, salty, high-calorie "junk food" and the rise of sedentary lifestyles. It is a major risk factor for heart disease and stroke, diabetes, arthritis and certain cancers. Chronic complications of weight kill about 3.4 million adults annually, the U.N. World Health Organization says. 
 
 During the 33 years studied, rates of being obese or overweight soared 28 percent in adults and 47 percent in children. During that span, the number of overweight and obese people rose from 857 million in 1980 to 2.1 billion in 2013. 
 
 That number exceeds the total world population of 1927, when it first hit 2 billion. Earth's population now tops 7 billion. 
 
 The researchers said obesity - once a malady of rich nations - now grips people of all ages, incomes and regions, with not one country succeeding in cutting its obesity rate. 
 
 "Two-thirds of the obese population actually resides in developing countries," said Marie Ng, a global health professor who was one of the researchers. 
 
 The problem was most acute in the Middle East and North Africa, with more than 58 percent of adult men and 65 percent of adult women overweight or obese. Bahrain, Egypt, Saudi Arabia, Oman and Kuwait saw big increases. 
 
 "We have to remind ourselves that obesity is really not a cosmetic issue. It's a main risk factor for morbidity and mortality," added global health professor Ali Mokdad, another of the researchers. 
 
 Obesity is appearing at increasing young ages, rising nearly 50 percent in children and adolescents worldwide. 
 
 Men tallied higher rates in developed countries. Women did so in developing countries. There was a possible ray of hope in rich countries, with the rate of increase in adult obesity slowing in the past eight years. 
 
 More than half of the world's obese live in just 10 countries: the United States, China, India, Russia, Brazil, Mexico, Egypt, Germany, Pakistan and Indonesia. 
 
 (Reporting by Will Dunham; Editing by Lisa Shumaker)
– There are more obese or overweight people in the world today than there were people of any weight in 1935, the most comprehensive look at worldwide obesity in decades warns. The 188-country study found that there are 2.1 billion overweight or obese people in the world, making up around 30% of the world's population, up from 20% in 1980, USA Today reports. Not a single country has recorded a decline in obesity over the last 30 years. "We hoped there would be some examples of success that you could latch onto," a study co-author says. "But there's a complete lack of success stories in bringing down obesity." The study published in British medical journal the Lancet found that the Middle East and north Africa had seen the biggest weight gains, though the US still has the largest number of obese people, with 87 million of the world's 671 million obese people, reports Reuters. Other countries, however, have even higher obesity rates, including Tonga, where more than 50% of all adults are obese. "Two-thirds of the obese population actually resides in developing countries," says one of the researchers; they warn that obesity rates are rising among rich and poor countries, men and women, and adults and children alike.