In the past few years, the growing rate of childhood obesity has alarmed researchers in the United States. Now, a recent study shows that the problem is not just an American one. The number of overweight children around the world is rising quickly.

The study, published in the International Journal of Pediatric Obesity, says that by 2010, about half of the kids in North and South America will be overweight. That is almost double the current rate of about one-third of the population.

Researchers say the rise is caused by an increase in kids eating junk food and a decrease in the amount of exercise kids get. The International Obesity Task Force released the study after analyzing worldwide trends in childhood obesity.

The study predicts that obesity rates of all children in the European Union will rise from the current rate, 25 percent, to 38 percent by 2010. The rate of obesity is also expected to rise in the Middle East and Southeast Asia.

"We have a truly global epidemic which appears to be affecting most countries in the world," said Dr. Philip James, chair of the International Obesity Task Force.

James said the epidemic has "enormous health consequences." Being overweight can lead to diseases such as diabetes, high blood pressure, cancer and other serious health problems.