A global study of adults and children finds that worldwide obesity rates have skyrocketed over the last 30 years, suggesting urgent steps are needed to reverse this public health crisis.

More than 2 billion people, or nearly 30 percent of the world’s population, are either obese or overweight, according to a new global study published in the Lancet.

Conducted by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, the study looked at data from 188 countries during the period from 1980 to 2013.

The study found that the highest proportion of the world’s obese people (13 percent) live in the U.S.

China and India together represent 15 percent of the world’s obese population. 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.

Over the course of the study, the researchers found that rates of overweight and obesity for men soared from 29 percent to 37 percent, while rates for women spiked from 30 percent to 38 percent.

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Dr. Christopher Murray, director of IHME and a co-founder of the Global Burden of Disease (GBD) study, said in a press statement, “Obesity is an issue affecting people of all ages and incomes, everywhere. 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.”

Obesity has increased substantially worldwide in children and adolescents. In fact, between 1980 and 2013, the prevalence of overweight or obese children and adolescents increased by nearly 50 percent.

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. In the developing world, rates are also on the rise among children and adolescents. Almost 13 percent of boys and more than 13 percent of girls are overweight or obese.

In the Middle East and North African countries, high rates of child and adolescent obesity were seen, especially among girls.

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“The rise in obesity among children is especially troubling in so many low- and middle-income countries,” Marie Ng, assistant professor of Global Health at IHME and the paper’s lead author, said in a statement.

Ng added, “We know 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.”

Commenting on the study’s findings, Alissa Rumsey, RD, CDN, CNSC, CSCS, a registered dietitian and spokesperson for the New York State Dietetic Association, told Healthline, “Obesity is a complex issue, and slowing down the increase of it is going to take large-scale efforts and policy change at a global, local, family, and individual level. Given how difficult it is to lose weight once someone becomes obese, prevention is key. Nutrition education needs to occur starting at a young age, and means getting the whole family involved.”

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Rumsey went on to say that people need to consume diets loaded with vegetables, fruits, whole grains, and legumes. She advised limiting high calorie sweets, treats, and snack foods. “While limiting food intake is the main predictor of weight loss, physical activity is one of the best predictors to keeping the weight loss off and maintaining a healthy weight,” said Rumsey.

Adults should aim for 30 to 60 minutes of physical activity at least five days per week, advised Rumsey. “This doesn’t mean you need to be in the gym for an hour. Take the stairs instead of the escalator, go for a 15 minute walk during lunch, park your car far away to get in more steps – every bit counts,” she said.

The World Health Organization’s (WHO) Director-General, who recently established a high-level Commission on Ending Childhood Obesity, said in a statement, “Many countries are experiencing a rapid rise in obesity among infants and children under five years of age. Tackling childhood obesity now represents an important opportunity to reduce the impact of heart disease, diabetes, and other serious diseases in the future – while immediately improving the health of children.”

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