Diabetes is incurable and can lead to heart disease, kidney failure and blindness if not properly managed, according to the WHO. It said more than 80 percent of Chinese people aged 11 to 17 are not getting enough physical exercise and noted that rates of obesity in children are increasing rapidly.

Yang Wenying, chairwoman of the Diabetes Branch of the Chinese Medical Association and a professor of metabolic diseases at China-Japan Friendship Hospital, said Type 2 diabetes rates are rising fast among the under 14s. "There are no official figures for the number of patients within that age group, but doctors have noticed an increasing number of such patients in recent years, and most of them are obese," she said.

One reason why there is a growing number of overweight, sedentary children may lie in the nation's family planning policy over the past several decades, and the fact that many families have a sole child who is doted on and may be overfed, she said.

More than 5.8 million Chinese children under 5 are overweight-about 7 percent, according to a nutrition report released by the Global Alliance for Improved Nutrition, an international organization launched by the United Nations in 2002. The number of overweight people under 20 rose by more than 200 percent between 1980 and 2013, the report said.

Liang Xiaofeng, deputy chief of the Chinese Center for Disease Control and Prevention, said a modern sedentary lifestyle contributed to the sharp rise in diabetes in China.

He said many schools lack exercise facilities, and teachers are generally reluctant to lead physical activities because of fears that students could be injured.

"All of us can do more to reduce our own risk - by healthy eating, and getting more exercise. Governments at all levels and the broader community also have a role to play - to make healthy choices easier for everyone," Schwartlander said.