Childhood obesity is a significant public health concern worldwide. In China, childhood obesity has dramatically increased as the economy has grown quickly over the past decades. Effective strategies to reduce childhood obesity prevalence may help to prevent related chronic diseases in the whole population in the long term.

This study aimed (1)to assess the effectiveness of the intervention compared with the usual practice in preventing childhood overweight and obesity; (2) to determine the sustainability of the intervention in preventing overweight and obesity; and (3) to evaluate the process and health economics of the intervention.

The project will be carried out in six primary schools in Ningbo City, Zhejiang Province , those schools are randomly divided into two groups: the intervention group and the usual practice group. The participants of the study were students in the third grade of primary school, and the intervention will last for one academic year. This intervention programme will target the influencing factors of childhood obesity at both individual (student-focused activities) and environmental levels (a supportive family and school environment), with the intent to influence the knowledge, attitude and behaviours of school children.

Inclusion Criteria:

• Parents agree and support their children's weight loss, and students and parents have informed consent;
• Students in third grade aged 8 to 10 years old.

Exclusion Criteria:

• medical history of heart disease, hypertension, diabetes, tuberculosis, asthma, hepatitis or nephritis;
• obesity caused by endocrine diseases or side effects of drugs;
• abnormal physical development like dwarfism or gigantism;
• physical deformity such as severe scoliosis, pectus carinatum, limp, obvious O-leg or X-leg;
• inability to participate in school sport activities;
• a loss in weight by vomiting or taking drugs during the past 3 months.