Poor compliance with school food environment guidelines in elementary schools in Northwest Mexico: A cross-sectional study

Predicted impact of banning nonessential, energy-dense food and beverages in schools in Mexico: A microsimulation study

BACKGROUND

Childhood obesity is a growing concern worldwide. School-based interventions have been proposed as effective means to improve nutritional knowledge and prevent obesity. In 2023, Mexico approved a reform to the General Education Law to strengthen the ban of sales and advertising of nonessential energy-dense food and beverages (NEDFBs) in schools and surroundings. We aimed to predict the expected one-year change in total caloric intake and obesity prevalence by introducing the ban of NEDFBs sales in schools, among school-aged children and adolescents (6 to 17 years old) in Mexico.

METHODS AND FINDINGS

We used age-specific equations to predict baseline fat-free mass (FFM) and fat mass (FM) and then estimated total energy intake (TEI) per day. The TEI after the intervention was estimated under 4 scenarios: (1) using national data to inform the intervention effect; (2) varying law compliance; (3) using meta-analytic data to inform the intervention effect size on calories; and (4) using national data to inform the intervention effect by sex and socioeconomic status (SES). We used Hall's microsimulation model to estimate the potential impact on body weight and obesity prevalence of children and adolescents 1 year after implementing the intervention in Mexican schools. We found that children could reduce their daily energy intake by 33 kcal/day/person (uncertainty interval, UI, [25, 42] kcal/day/person), reducing on average 0.8 kg/person (UI [0.6, 1.0] kg/person) and 1.5 percentage points (pp) in obesity (UI [1.1, 1.9] pp) 1 year after implementing the law. We showed that compliance will be key to the success of this intervention: considering a 50% compliance the intervention effect could reduce 0.4 kg/person (UI [0.3, 0.5] kg/person). Our sensitivity analysis showed that the ban could reduce body weight by 1.3 kg/person (UI [0.8, 1.8] kg/person) and up to 5.4 kg/person (UI [3.4, 7.5] kg/person) in the best-case scenario. Study limitations include assuming that obesity and the contribution of NEDFBs consumed at school remain constant over time, assuming full compliance, and not considering the potential effect of banning NEDFBs in stores near schools.

CONCLUSIONS

Even in the most conservative scenario, banning sales of NEDFBs in schools is expected to significantly reduce obesity, but achieving high compliance will be key to its success.

WHY WAS THIS STUDY DONE?

- School-based interventions have been recognized as effective means to improve nutritional knowledge and prevent obesity-related diseases.- In December 2023, the Chamber of Representatives of Mexico approved an amendment that strengthens and updates the General Education Law (Article 75) and nutritional guidelines to ban the sales and advertising of nonessential energy-dense food and beverages (NEDFBs) in schools.

WHAT DID THE RESEARCHERS DO AND FIND?

- We used age-specific equations to predict baseline fat-free mass (FFM) and fat mass (FM) and total energy intake (TEI) per day.- We used microsimulation modeling to predict body weight and obesity prevalence of children and adolescents 1 year after implementing the intervention in Mexican schools.- Our modeling study suggests that an important impact on obesity prevalence can be expected if the law is implemented and enforced as intended.

WHAT DO THESE FINDINGS MEAN?

- If successful, this law could serve as an example beyond Mexico on how to achieve changes in body weight through school food regulation.- An important limitation of our main scenario is that we assumed full compliance of schools with the law, yet lower compliance will reduce its impact. We also did not consider historical trends on obesity or NEDFBs consumed in schools during our 1 year simulation, and we considered only the ban impact inside schools, excluding effects near and outside schools.

Self-efficacy and Social Settings Matter for Fostering Healthy Eating in Mexican Schoolchildren

OBJECTIVE

To identify differences in schoolchildren's self-efficacy for eating behaviors across social settings and self-efficacy sources favoring healthy and unhealthy eating.

DESIGN

A cross-sectional, mixed-methods study using self-efficacy and demographic surveys, focus groups, and school environment semistructured observations.

SETTING

Morelos, Mexico, Cuernavaca City school district, public elementary schools in the National School Lunch Program.

PARTICIPANTS AND RECRUITMENT

We studied 274 fifth- and sixth-grade children from 8 elementary schools during the 2016-2017 school year.

VARIABLES MEASURED

Children's self-efficacy for healthy and unhealthy eating across 3 settings (school cafeteria, recess, and home). Children's perceptions about sources of self-efficacy, which favor their healthy or unhealthy eating (performance accomplishments, behavior modeling, verbal persuasion, and emotional or physiological states). Sociodemographic information was obtained from parents.

ANALYSIS

We performed a variance components analysis with school and students within schools as random effects with paired t tests (quantitative data) and content analysis on the basis of the Social Cognitive Theory (qualitative data).

RESULTS

Schoolchildren's self-efficacy for healthy eating differed across social settings, being greater in the school cafeteria than at recess or home, except for drinking water. On average, self-efficacy for unhealthy eating was lower in the cafeteria than in other studied settings. Performance achievements and behavior modeling were key sources of self-efficacy for healthy and unhealthy eating.

CONCLUSION AND IMPLICATIONS

Sources of self-efficacy and social settings matter to understanding schoolchildren's healthy and unhealthy eating. Future interventions might consider developing collective efficacy among the school community and boosting children's participation in home meal planning. Further research could explore locus of control and other intrapersonal dimensions influencing self-efficacy.