More than 16 percent of Shanghai kids are obese - seriously overweight - and it's urgent that they shed pounds, exercise and eat right.

Doting parents and grandparents must tell them "no." Zhang Qian weighs in. When Li Sumei brings out the soup, she is surprised to see that her 11-year-old grandson has already finished off a big dinner, wolfing down a chicken leg, several meat balls and a bowl of rice. Now he is eagerly awaiting the soup.

The boy is now 1.42 meters tall and weighs 48 kilograms. He is obese. His body mass index (BMI) is 24 - 22 is definitely overweight.

Li knows it too, but the typically indulgent grandmother just can't deny her grandson another helping. The boy knows it too, but when he sits down to eat, he has no self control - young brains are not fully developed and there's poor impulse-control.

There's a Chinese saying that child with a round broad face, like a tiger's, is sturdy, healthy and smart - but it doesn't mean fat. "Tiger head, tiger brain" ("hu tou hu nao"), it goes.

Chunky sturdy kids are not the problem. Fatties are, both kids who are overweight and those who are obese, a more serious condition.

China's rapid economic development and higher income, the taste for fast-food and more sedentary lifestyles have resulted in rapid weight gain by the population as a whole in the past 20-30 years - and this includes obesity and health problems.

The rate of obesity among Chinese adults has increased from 6 percent to 22.8 percent in the 10 years from 1982 to 2002, according to the national Chinese Resident Nutrition and Health Report 2002. The rate is also increasing for children, and it's quite apparent.

The number of overweight and obese children in China has reached 12 million, accounting for one-third of the world's fat kids, according to the 2009 Chinese Child Nutrition and Health Report. It's based on studies conducted by the Chinese Association for Student Nutrition and Health Promotion.

The report also says the rate of overweight and obesity among children seven to 17 years of age has tripled to 8.1 percent in the past 10 years. It's expected to climb quickly.

"Without proper and timely intervention, the rate of obesity for Chinese children may quickly catch up with the rates for Europe and America," says Ma Guansheng, vice president of Chinese Association for Student Nutrition and Health Promotion.

The situation is worse in big cities like Shanghai, according to Dr Tang Qingya, director of the Clinical Nutrition Center of Xinhua Hospital.

The rate of obesity (seriously overweight, not just heavy) for young people up to 18 years of age reached 16.1 percent in 2007. More recent statistics are not available, but the rate has clearly gone up. If overweight kids were counted, the rate would be extremely high.

BMI, or body mass index, used to assess healthy adult body weight can also be applied to kids, though the standard is different depending on age and sex, says Dr Hong Li, chief of the Clinical Nutrition Department of Shanghai Children's Medical Center.

BMI is body weight divided by the square of his or her height; though it does not specifically measure fat, it's a good indicator of weight problems.

For adults, a BMI of 24 is a warning. For children, the figure ranges from 17 to 22, depending on age and sex. A child with a BMI over 22 is definitely overweight.

Being fat, of course, is not only an appearance problem but also poses threats to health. Chronic ailments like high blood pressure, diabetes and high blood fat are also found among fat children today. Moreover, accumulated fat and cholesterol clog arteries and put stress on the organs. Too much fat can damage the respiratory system, digestive system, immune system and internal secretion system.

Experts say the risk of high blood pressure is three to four times higher for fat (both overweight or obese) children than those of average weight. The occurrence of digestive problems is 15 percent for fat kids, compared with 4 percent for kids of average weight. The rate of fatty liver among fat kids is as high as 80 percent.

Being fat also has social and emotional consequences.

"Some fat kids lack self-confidence and are unsociable as they cannot move as quickly as others," says Dr Tang.

Fat kids are often teased and shunned by other kids, which increases their isolation.

Improper diet is the major cause. Many parents serve their only child whatever he or she wants to eat and most kids themselves have not developed self control about eating.

Rampant snacking makes things worse.

Lack of knowledge about health and nutrition contributes to the problem.

The case of Li Sumei and her grandson is typical.

"I know he is fat and he also knows he needs to lose weight," says Li. "But whenever he starts eating, he forgets about losing weight and I cannot stay tough and take the food away."

Lack of regular physical exercise aggravates the problem. Using computers and watching TV has replaced physical exercise for many youngsters, as well as adults. Taking taxis and elevators replace walking and taking the stairs.