There has been a tenfold rise in the number of obese children and adolescents (aged 5-19) worldwide over the past 40 years, a study by the World Health Organization and Imperial College London found. The study found that the rise is accelerating in low and middle-income countries, especially in Asia.

“Over the past four decades, obesity rates in children and adolescents have soared globally, and continue to do so in low- and middle-income countries,” lead author Professor Majid Ezzati, of Imperial’s School of Public Health said. If current trends continue, in 2022 there will be more obese children and teenagers across the world than underweight ones.

Polynesia and Micronesia had the highest rates of child obesity last year – 25.4% in girls and 22.4% in boys. The “high-income English-speaking region”, which includes the United States, Canada, Australia, New Zealand, Ireland and Britain followed. Among high-income countries, the United States had the highest obesity rates for girls and boys – at 19.5% and 23.3%, the report said.

India, meanwhile, has the highest number of underweight children over the last four decades. The study said of the 19.2 crore of world’s moderately or severely underweight children and adolescents, 9.7 crore– or more than half – lived in India in 2016.

How the study was done

The study analysed the weight and height of 13 crore people aged over five (3.15 crore people aged 5 to 19, and 9.74 crore aged 20 and older). This is the largest number of participants ever involved in an epidemiological (deals with the incidence, distribution, and control of diseases) study. More than 1,000 researchers contributed to the study, which looked at body mass index and obesity from 1975 to 2016. BMI is a measure of a person’s weight and body fat mass for their height, and indicates whether their weight is healthy.