Implementation and impact of the ban on the sale of ultra-processed foods to minors in Mexico
Lead Research Organisation:
National Institute of Public Health INSP
Department Name: Center for Nutrition and Health Research
Abstract
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.
Technical Summary
On August 2020 the state of Oaxaca in the south of Mexico approved a new law that bans the sale, distribution and donation of packaged ultra-processed foods (UPFs) and beverages to minors. This is an unprecedented obesity prevention policy which equates UPFs to other harmful products such as alcohol and tobacco. This proposal aims to evaluate the implementation and impact of this age-of-sale law. This is a milestoned proposal organized in two stages. In stage 1 we will use Proctor's Implementation Outcomes Framework and associated Constructs from the Consolidated Framework for Implementation Research (CFIR) to investigate implementation outcomes (acceptability, appropriateness, feasibility, cost, adoption and fidelity) and their determinants. We will conduct surveys and semi-structured interviews with implementation actors and will complement this information with a mystery client study; where children and adolescents will attempt to purchase banned products in stores and schools. The project will progress onto stage 2 if the mystery client study finds that at least 20% of schools and food outlets have implemented the law. In the second stage we aim to evaluate the impact of the law on dietary outcomes, specifically dietary energy contribution from UPFs, processed foods and unprocessed foods, and overweight and obesity prevalence. We will leverage data from six waves of Mexico's National Health and Nutrition Surveys to estimate pre and post intervention estimates for the outcomes of interest for Oaxaca and comparison states. The analyses will use difference-in-difference fixed effects models to estimate impact. The results of this study will be used as rigorous evidence to justify roll-out in other geographies if the policy is found to be effective. If effectiveness is found to be limited or null, our study will help to understand why, to make changes if possible, or to abandon this strategy in favor of other approaches.
| Description | Training for schools and co-desing of implementation strategies |
| Geographic Reach | Local/Municipal/Regional |
| Policy Influence Type | Influenced training of practitioners or researchers |
| Impact | The following abstract accepted at the Public Health Research Conference 2025 (https://congisp.insp.mx/) describes the outcomes measured and results. Background In 2020, Oaxaca banned the sale and distribution of ultra-processed products to minors. In 2023, an implementation science study documented various barriers to the law's adoption and implementation, which may limit its effectiveness. Here we present the findings of a pilot workshop aimed to increase educators' knowledge of the law, identify strategies to address its implementation barriers, and assess their perceptions of its acceptability, appropriateness, and feasibility. Methods The workshop was conducted in September 2024 in two stages. First, participants received training on the legislation and sales regulations through a theoretical session and a collage-based participatory activity called "My Healthy Store." Then, a collaborative mapping exercise was carried out to identify potential strategies to address 25 previously identified implementation barriers. The workshop was evaluated using a pre-post questionnaire designed to measure changes in knowledge about the law and perceptions of its acceptability, appropriateness, and feasibility using validated 5-point ordinal scales. Results The workshop included 82 participants (11 principals , 5 teachers, and 52 parents), 40% of whom were aware of the law at baseline. Before the workshop, only 17% of the participants could correctly identify three foods allowed by the law, but this increased to 60% after the workshop (P<0.001). Baseline scores for acceptability, appropriateness, and feasibility, respectively, raised from 3.88, 3.73, and 3.52 at baseline to 4.73, 4.42, and 4.15 in the post-test, with significant differences across all three key measures (P<0.001). Five to twelve implementation strategies were identified for each of the 25 barriers . Conclusion This pilot workshop led to an increase in knowledge and key adoption and implementation predictors. It also helped identify implementation strategies in collaboration with key stakeholders. Designing and implementing a bundle of implementation strategies from the subset of those identified that address implementation barriers could enhance the law's adoption and implementation. |
| Title | Implementation outcomes dataset |
| Description | This dataset consists of 97 variables and 234 unique observations for schools and stores, as of March 2024. The dataset was created from primary data gathered by our team in Oaxaca, from November 2023 to may 2024, using a digital interface built with REDCap. The information contained in this dataset pertains to the mystery client study (N=125 purchase attempts) and surveys of implementation actors (N=109). This dataset will allow us to describe and analyse the following implementation outcomes for the law in Oaxaca: adoption, fidelity, acceptability, appropriateness and feasibility. The dataset does not yet have a DOI since it is not final. Once it is, it can be shared after removal of any identifiable information from stores and schools. A detailed codebook is available. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2024 |
| Provided To Others? | No |
| Impact | This dataset was analysed during 2024. Preliminary results have been presented to school directors and teachers in a workshop in Oaxaca (Sept 2024), see entry under influence of patients and public. Preliminary results have also been presented at the Public Health Research Conference in March 2025. The results will help us advocate for better implementation efforts of nutrition policy in schools in a future publication. |
| Title | Qualitative data: implementation determinants |
| Description | Recordings and transcripts for 20 semi-structured interviews. Interviewees are implementation actors from the following sectors: Ministry of Health, Ministry of Education, schools, stores, local government (municipalities), local policy makers and the local human rights monitoring system. Our interviews aim to understand the determinants of implementation outcomes based on the Consolidated Framework for Implementation Research. We will continue to interview implementation actors until we reach saturation, therefore this resource will grow. Interview recordings and transcripts will not be shared outside of our research group since they contain personal information. A master project has been created in Atlas.ti with these data and is being analysed by two researchers. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2024 |
| Provided To Others? | No |
| Impact | These data have not yet had an impact. They are very new and are currently being analysed. |
| Description | Collaboration between INSP (two research groups), Yale University, University of Texas and National Cancer Institute of Mexico |
| Organisation | University of Texas at Houston |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | The 2024 implementation Science summer course hosted by INSP was held in collaboration with project LISTOS (funded by NCI), National Cancer Institute of Mexico, University of Texas Houston and University of Yale. Carolina Pérez Ferrer (PI) served as tutor of the course while Prof Donna Spiegelman and Dr. Raul Hernandez (Co-Is of the project) delivered lectures. Our project paid for 4 scholarships, and simultaneous translation for Prof Donna Spiegelman. Mariana Lopez, project research assistant was a participant in the course. The course was attended by 17 participants (participation was capped to allow for a more intensive experience) and had a duration of 40 hours over four weeks. |
| Collaborator Contribution | Our partners collaborated in the course design and lectures. Lecturers and tutors from the other institutions included: Prof Maria E. Fenandez, Dr Martin Lajous and Dr Karla Unger. |
| Impact | The output was the course attended by 17 students which received positive reviews. |
| Start Year | 2024 |
| Description | Collaboration with Yale University |
| Organisation | Yale University |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | The PI and research team in Mexico have led the project ensuring regular communication with our partners at Yale. We have meetings every fortnight, and email communication in between meetings. We provide the day-to-day operation of the project as well as the local expertise. Our research team coordinated a recent visit of our partners to Mexico. Over this visit they met with INSP researchers who are interested in submitting proposals which involve implementation science frameworks and methodologies. New projects would ensure that we continue the collaboration once this project finishes. |
| Collaborator Contribution | Our collaborators at Yale University have provided technical advice and their expertise in implementation science at each step of our project. Specifically: study design, sampling design and procedures, data collection instruments, data management plans and analyses plans. They have invited us to their seminar series where state of the art methodologies for implementation research are presented. This collaboration has been key to the development of skills for staff in Mexico who were trained in traditional public health and epidemiology but newer to implementation science research methods and practice. Our partners participated as lecturers in the Implementation Science summer course 2024 (see other entry under collaboration Yale-UTexas-INSP-Cancer Institute). And more recently, in March 2025 they visited Mexico to teach a pre-conference workshop on implementation science study designs for complex and multicomponent interventions and to participate in a seminar where the results of our study were presented as well as results from other studies using implementation science frameworks and methodologies. The pre-conference workshop was attended by 30 participants and was very well evaluated. |
| Impact | The main outputs of this collaboration is a dataset and qualitative data (semi-structured interviews). These are described in more detail in the relevant sections. This collaboration is multi-disciplinary and involves biostatistics, epidemiology, implementation science and public health. Other outputs include a workshop on study designs for complex and multicomponent interventions, including materials. |
| Start Year | 2023 |
| Description | Collaboration with the Ministry of Health of Oaxaca |
| Organisation | Mexican Ministry of Health (SSA) |
| Country | Mexico |
| Sector | Public |
| PI Contribution | Our contribution is to evaluate the implementation of the law that bans the sale of ultra-processed foods to minors. The Ministry of Health (MoH) is responsible for its applications and enforcement, however due to other priorities, has not given it enough attention. To evaluate implementation we have done the following (as per our project protocol): carried out a mystery client study in schools and stores to evaluate adoption of the law that bans the sale of ultra-processed schools to minors (N=125 purchase attempts), evaluated acceptability, appropriateness and feasibility among implementation actors with short surveys (N=109) and carried out 20 semi-structured interviews with implementation actors. Once we have results from our project, we will be sharing them with the MoH including recommendations for better implementation. |
| Collaborator Contribution | The MoH provided logistical support for data collection during November and December 2023 and during April and May 2024. Specifically, they provided two vehicles with drivers for three weeks to visit schools and stores in the state of Oaxaca. They have also been supportive to arrange interviews with implementation actors which has been crucial for our project. |
| Impact | The outputs are the datasets and qualitative data generated during November and December 2023 and April, May 2024. |
| Start Year | 2023 |
| Description | An article in INSP's magazine |
| Form Of Engagement Activity | A magazine, newsletter or online publication |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Postgraduate students |
| Results and Impact | An article was published in the magazine "Gaceta INSP" which is one of the main research dissemination channels of the National Institute of Public Health. Gaceta INSP is a print and online magazine intended to communicate the work that is carried out at the institute, including research findings, to a wide audience including INSP's postgraduate students, other researchers and the general public (it's content is shared on social media). The title of the article was "Implementation science vs ultra-processed foods". For this article, two researchers from our project were interviewed (Carolina Pérez and Raul Hernández). The article was written when our project was just beginning and describes the rationale for the project and the main objectives. It mentions the funding from the MRC. This article was published online and can be consulted in the link below (reach of 550 through the link). It was also shared on social media with a reach of 3,263 impressions on Facebook and 530 impressions on Twitter. This article promted questions and interest on our project from students and potential research assistants. Link to Volume 18 of Gaceta INSP: https://gaceta.insp.mx/vol-18/ Link to the article within volume 18 of Gaceta INSP: https://gaceta.insp.mx/ciencias-de-la-implementacion-vs-los-ultraprocesados-2/ |
| Year(s) Of Engagement Activity | 2023 |
| URL | https://gaceta.insp.mx/ciencias-de-la-implementacion-vs-los-ultraprocesados-2/ |
| Description | An article in INSP's magazine about data collection in Oaxaca |
| Form Of Engagement Activity | A magazine, newsletter or online publication |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Professional Practitioners |
| Results and Impact | An article about doing fieldwork in Oaxaca was published in the National Institute of Public Health magazine (Gaceta INSP). The intention of the article was to share some of the challenges we faced when planning our fieldwork and how we overcame them. We felt this could be interesting and useful for other colleagues planning data collection in communities and we also wanted to share how through partnerships with local organisations and local government we were able to overcome many logistical and administrative challenges. |
| Year(s) Of Engagement Activity | 2024 |
| URL | https://gaceta.insp.mx/experiencias-de-trabajo-de-campo-para-la-evaluacion-de-la-implementacion-de-l... |
| Description | Feedback to school food policy draft |
| Form Of Engagement Activity | A formal working group, expert panel or dialogue |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Policymakers/politicians |
| Results and Impact | Dr Anabelle Bonvecchio, co-I of our project was asked to comment and give feedback on the new guidelines for the sale of food in schools. The guidelines were published in November 2024. |
| Year(s) Of Engagement Activity | 2024 |
| Description | Meeting with school directors in Oaxaca |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Study participants or study members |
| Results and Impact | On February 2024, the PI met with the leader of a school district and a school director from the municipality of Etla in Oaxaca. This district has 18 primary schools. The meeting was requested as a result of our project's field work and data collection in November where one of the interviewed school directors mentioned she had very little information on the laws regulating the sale of food within schools and wanted to learn more. In the February meeting with the leader of the district and her we agreed two things: the first, our project will provide a description of the legal framework regarding the sale of food in schools in Mexico and second, we will explore delivering a workshop with school directors and parents of the school district to explain the legal framework and some ideas on how it can be better implemented at the school level. |
| Year(s) Of Engagement Activity | 2024 |
| Description | Meeting with the governor of Oaxaca and his team |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Policymakers/politicians |
| Results and Impact | On the 10th of March 2023, the PI assisted a meeting in the city of Oaxaca to present the project to the state government. The governor was present as well as the ministers for health and agriculture, the undersecretary for education, the governor's chief of staff, and two policy makers from the local congress. The intention of this meeting was to present the project and request support to ensure that project activities could be carried out safely. We also took the opportunity to present childhood overweight and obesity prevalence data, information on dietary practices and current laws and regulations to prevent childhood overweight and obesity. This included reminding them of the law that we are evaluating and opening a conversation about the lack of implementation actions that the previous government had carried out. We received positive feedback regarding our project and a promise of support that has been honored. It was also a good opportunity to bring up the issue of childhood obesity, which they acknowledged had not been given priority during the first 100 days of government. |
| Year(s) Of Engagement Activity | 2023 |