The three-year survey by the Capital Institute of Pediatrics (CIP) also revealed that 8.4 percent of the 23,400 respondents aged below 18 were obese. This was equal to 231,000 youngsters in the city.

In addition, nine percent of the respondents were troubled with high blood pressure. Another 9.8 percent had cholesterol problems, Monday's Beijing Morning Post cited the survey as saying.

Such chronic ailments that are commonly found in adults have been increasingly affecting young people, said Mi Jie, an expert with the CIP, the survey organizer.

The poll, which involved an investment of nearly 6 million yuan (about 822,000 U.S. dollars), is considered to be the most authoritative research on child health in Beijing to date.

Experts attributed child obesity to unhealthy dietary habits, less physical exercise, inadequate sleep and excessive amounts of salt in meals.

Obese kids are more prone to cardiovascular diseases and diet-related illnesses such as diabetes than children of normal weight, Mi said.

There are about 20 million people suffering from diabetes in China, according to the Ministry of Health. The number of child diabetes cases accounted for about five percent of all patients. The figure is increasing by 10 percent annually, Li Qiang, an endocrine secretion professor said.