英文摘要 （Abstract）

Over the past 30 years，childhood obesity has been growing at an alarming speed and become to be one of the serious public health concernsworld widely.

Along with the rapid transitions in social economic development and lifestyle，obesity among children in China showed anastonishing growing trend.In the 1980s，childhood obesity was neither epidemic nor a public health problem.However， from the beginning of the 1990s， childhood obesity showed a growing trend.A survey carried out in 9 cities of China showed that the obesity prevalence in children aged 0～7 years increased rapidly in the past 20 years between 1986 and 2006.The overall childhood obesity prevalencewas0.91%in 1986，0.90%for girls and 0.93%for boys， respectively.The overall overweight prevalence increased to 6.25%in 2006， 6.59%for boys and 5.88%for girls， respectively， while the overall obesity prevalence increased to 3.19%， 3.82%for boys and 2.48%for girls，respectively.

Similarly，the prevalences ofoverweightand obesity among studentswere still at low levels in the 1980s.The results of“The Physical Fitness and Health Research of Chinese School Students in 1985” showed that the prevalence of overweight and obesity in urban children aged 7～18 years was 1.3% ～1.6%，while 0.5% ～1.6%for their rural counterparts.By 2000，the overall prevalences of overweight and obesity among students aged 7～18 years had raised to 15.7%and 9.1%， respectively， where as those were 5.9%　and 4.6%　for rural students， respectively.Obesity has begun to be epidemic， especially in urban students.In the 21st century， the prevalences ofoverweightand obesity in students continued to rise.In 2014，the overall prevalences of overweight and obesity among students aged 7～18 yearswere 28.2%and 16.4%， respectively，while 20.3%and 12.8%for ruralstudents，respectively.Childhood obesity has become epidemic nationwide， especially in recent years，the growth rate of overweightand obesity in rural students is accelerating.

On the basis of the datamentioned above，it is predicted that if there is no intervention being taken， the prevalence of obesity in children aged 0～7 years would reach 4.8%by 2020 and 6.0%by 2030， respectively， while the number of obese children would reach 5.31 million and 6.64 million， respectively.At the same time， the prevalences of overweight and obesity in student aged 7～18 years would reach 22.3%and 28.0%， respectively， while the number of obese students would be as high as 39.41 million and 49.48 million，respectively.

Obesity is a chronic metabolic disease caused by various factors.Obesity-related genes play an important role in the occurrence and development of obesity.In recent years，studies focusing on obesity-related genes have found that a variety of genes including FTO gene having a bearing on the occurrence of obesity.However，over the past decades， the rapid growth ofobesitywas actually not caused by the change of genes but the behavioral and environmental factors.These factors were themain reasons for the rapid growth of childhood obesity in China，including transitions in the environment leading to obesity，behavior and lifestyles， food supply and consumption， and in physical activity as well.

Together with the change of transport and lifestyle，the opportunity for students to go to school by vehicles is becomingmore and more common，while those by cycling orwalking are less and　less.The　excessive　learning　burden　also　makes　them　have　less　time　for outdoor activities.Besides， attracted by televisions， computers and mobiles make children and adolescents spend more and more time on screens.The changes in dietary behaviors of children and adolescents also affect the occurrence of overweight and obesity.Asmentioned in the Report of the Survey on the Nutrition and Health Status of Chinese School-age Children and Adolescents in 2011， unhealthy dietary behaviors such as skipping the breakfast， eating out frequently， having unhealthy snacks and drinking sugar-sweetened beverageswere very common among Chinese children and adolescents.

Obesity is not only a disease but also the risk factor for variety of chronic diseases.The increasing of childhood　obesity has led　to the chronic diseases occuring　in　the　younger age.Overweight and obesity has become a major risk factor for childhood cardiovascular disease and type2 diabetes.Overweightand obese children are athigher risk of having abdominal obesity，impaired glucose tolerance and high blood pressure.

The Chinese residents’ nutrition and chronic disease status report（2015）pointed out that the chronic diseasemortality rate in 2012 was 533/100 000，accounting for 86.6%of the total deaths.The cardiovascular and cerebrovascular disease，cancer and chronic respiratory diseases were themain cause of death，accounting for 79.4%of total deaths.Chronic disease has become a great threat to our lives and health， aswell as themain burden of diseases， which brings heavy pressure to the national health care system，and also becoming the constraint for the quality of the population health and the social economic development.Therefore，reducing the economic burden of chronic diseases through the prevention and control of childhood obesity is an urgentmeasure for the government.

Childhood is the key stage for fostering healthy behavior and lifestyle.Once it is formed during childhood，itwill sustain throughout the lifetime.Healthy behavior and lifestyle not only ensure the normal growth and development of children，but also have long-term benefit for their lifetime health and happiness.

Although the epidemic of childhood obesity in China started later than that in developed countries，it is urgent to aware that it is at the crucial stage of rapid growth now.It is the best time for prevention and control.If we can take the chance to take effectivemeasures，we can get amultiplier effect.Otherwise， no actions were taken against children′s obesity will bring a heavy burden and huge loss to the health，quality of life and socio-economic development.It is found that the implementation of comprehensive obesity intervention could play a better prevention role on the control of development of childhood obesity.From the perspective of health economics，the costbenefit ratio could reach 1∶1.2.

Based on both domestic and international literatures，this report describes the prevalence and trend of childhood obesity， the environmental factors leading to obesity， the existing policies and actions，the cost-effectiveness of childhood obesity control and intervention.We hope this report could provide suggestions for the development of strategies and measures for childhood obesity prevention and control in China.

This reportwas drafted by the editorial board by referring to the latest literatures in childhood obesity research in China，and then solicited opinions widely， discussed and revised for two years.The references updated until December 1st，2016.This report will be updated as the research being updated.There are also some shortcomings in the report，comments from experts and readers are welcome.