Objective: To evaluate the impact of food advertising on childhood obesity by reviewing relevant literatures, and to provide evidence support for childhood obesity prevention and control strategies in China. Methods: A systematic review method was used to search relevant literatures published to November 30，2020 from 8 databases including CNKI, VIP, Wanfang Data, PubMed, Medline, SpringerLink, Web of Science, Science Direct. The high quality systematic reviews published since 2016 were included directly, and those published before 2016 were rereviewed after combined with other literatures. Results: A total of 13 articles were included for evaluation, including systematic reviews, cohort studies, randomized controlled trials and cross sectional studies. Children s exposure to food advertisements could increase energy intake. Television food advertising could influence children s food choices and increase the consumption of unhealthy foods such as sweets and sugary drinks. Children s exposure to unhealthy food advertisements could increase the risk of obesity. Conclusion Regulating the food advertisement can help reduce the risk of childhood obesity.

Objective: To evaluate the impact of sugar sweetened beverages (SSBs) tax on childhood obesity by literatures reveiew, and to provide evidence support for childhood obesity prevention and control strategies in China. Methods: A systematic review method was used to search relevant literatures published to November 30，2020 from 8 databases including CNKI, VIP, Wanfang Data, PubMed, Medline, SpringerLink, Web of Science, and Science Direct. The high quality system reviews published since 2016 were included directly, and those published before 2016 were rereviewed before combined with other literatures. Results: Twelve studies including 5 systematic reviews (or Meta analysis), 1 cohort study and 6 cross sectional studies were included. Comprehensive analysis showed that the prevention effect on childhood obesity was small or even ineffective if the tax on SSBs lower than 5%, a certain protective effect on childhood obesity could be shown if the tax on SSBs increased to 20%. From the perspective of cost benefit analysis, the implementation of SSBs tax showed certain net benefits. Conclusion SSBs tax can help reduce the risk of childhood obesity.

Objective: To evaluate the impact of community built environment and the distribution of fast food restaurants on childhood obesity, and to provide evidence support for childhood obesity prevention and control strategies in China. Methods: A systematic review method was used to search relevant literatures published to November 30，2020 from 8 databases including CNKI, VIP, Wanfang Data, PubMed, SpringerLink, Web of Science, Science Direct. The high quality system reviews published since 2016 were included directly, and those published before 2016 were reviewed before combined with other literatures. Results: A total of 20 articles were included for evaluation, including systematic reviews, cohort studies, randomized controlled trials and cross sectional studies. High walkability near the living area could increase children s physical activity levels and reduce the risk of obesity. The fast food sales environment increased the risk of obesity; while large supermarkets or health food sales environment could reduce the risk of obesity. Conclusion Improving walking suitability in residential areas and reducing the density of unhealthy fast food sales could help decrease the risk of childhood obesity.