Nearly 30 percent of the world’s population is considered overweight or obese, according to a new study.

No country has been able to successfully reduce obesity rates in the last 33 years. The increase in obesity rates across the globe over the last three decades has been substantial, sparking a major public health epidemic in both developed and developing countries.

The study conducted by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington showed that the number of overweight and obese people around the world rose from 857 million in 1980 to 2.1 billion in 2013.

Dr. Christopher Murray, director of IHME and a co-founder of the Global Burden of Disease (GBD) study, is concerned that obesity is a serious issue affecting people from all walks of life.

“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. Murray in a statement.

Although the obesity epidemic affects people from all across the globe, the highest proportion of the world’s obese individuals live in the U.S. India and China together represent 15 percent of the world’s obese population.

The rise in obesity levels among children and adolescents is especially troubling, particularly among low- and middle-income nations. The prevalence of childhood obesity has increased by almost 50 percent between 1980 and 2013.

The findings of the study are published in The Lancet.