Poor diet and nutrition may be behind an average height gap of 20cm between the tallest and shortest children in different countries. Researchers from Imperial College London conducted a global analysis of the Body Mass Index (BMI) of schoolchildren and adolescents around the world. This involved measuring the height and weight of millions of children and teenagers. They discovered that the world's tallest 19-year-olds, at 183.8cm, lived in the Netherlands, while the shortest, at 160.1cm, lived in East Timor. The researchers said teenagers in northwest and central Europe were the tallest in the world. On average the shortest children lived in South and South-East Asia, Latin America and East Africa.

The study was extremely comprehensive. It involved analysing data from 65 million children aged five to 19 years old in 193 countries. The researchers reported that children's height and weight varied enormously in different regions. The team warned that a lack of quality food and nutrition was a major factor behind stunted growth and a rise in childhood obesity. It said improved diets increased the average height of children in China. Nineteen-year-old boys there were 8cm taller in 2019 than in 1985. Researchers attribute this to improved nutrition. The lead author of the report urged countries to adopt policies that encouraged healthier eating, but to be aware of the perils of excessive weight gain.