Implementation and impact of the ban on the sale of ultra-processed foods to minors in Mexico

儿童肥胖仍然是全球的公共卫生问题，因此，有必要测试和评估新的预防政策和干预措施。这项研究将评估墨西哥瓦哈卡州禁止向未成年人销售超加工食品的新法律的实施情况和影响。在第一阶段，我们将调查和采访执行者，包括卫生部官员、市政当局和学校校长。我们将衡量执行结果，特别是政策是否为行为者所接受，是否被认为是可行的和相关的。同时，我们将进行一项神秘客户研究，儿童和青少年将试图从选定的社区零售商和学校食堂购买违禁产品。通过这项研究，我们将能够客观地衡量政策的采纳情况，以及政策是否得到了忠实的实施。如果我们发现超过20%的食品零售商和学校已经通过了这项法律（即他们不向未成年人出售超加工食品），那么研究将进入第二阶段，我们将衡量这项法律对儿童饮食和肥胖患病率的影响。为了做到这一点，我们将利用墨西哥六波国家健康和营养调查的数据来估计法律生效（2020年）前后的超加工食品消费和肥胖患病率。对于类似政策尚未获得批准的瓦哈卡州和比较州，也将这样做。这项研究的结果将显示该政策是否有效，是否可以成功实施并可能推广到其他地区。

Childhood obesity continues to be a public health issue globally therefore, it is necessary to test and evaluate new prevention policies and interventions. This study will evaluate both the implementation and impact of a new and unprecedented law that bans the sale of ultra-processed foods to minors in the state of Oaxaca, Mexico. In a first stage we will survey and conduct interviews with implementation actors including ministry of health officials, municipal authorities and school directors. We will measure implementation outcomes, specifically whether the policy is acceptable to actors, perceived feasible to implement and relevant. Simultaneously, we will conduct a mystery client study where children and adolescents will attempt to purchase a banned product from selected community retailers and school canteens. With this study component we will be able to objectively measure adoption of the policy and whether it is being implemented with fidelity. If we find that over 20% of food retailers and schools have adopted the law (i.e. they do not sell ultra-processed foods to minors), then the study will progress to stage 2 where we will measure the impact of the law on children's diet and obesity prevalence. To do this, we will leverage data from from six waves of Mexico's National Health and Nutrition Surveys to estimate ultra-processed food consumption and obesity prevalence before and after the law came into effect (2020). This will be done for Oaxaca and comparison states where a similar policy has not been approved. The results of this study will show whether the policy is effective, whether it can be successfully implemented and potentially rolled-out to other geographies.