Prevention of Eating Habits Associated With Obesity

This study evaluates the effectiveness of a Wise Intervention based on a values alignment approach to improve obesity-related eating habits in Spanish adolescents. Half of the participants will receive the experimental intervention, while the other half will receive a control intervention.

Obesity in adolescence is associated with physical and mental health problems and predicts obesity in adulthood. Adolescence may be an ideal time to target interventions, as this is when numerous health-related habits are consolidated. Several universal preventive interventions have been carried out in educational centers for the promotion of healthy eating habits. However, the results of reviews and meta-analyses have concluded that most are not cost-effective for producing long-term changes in the dietary preferences of young people. The so-called wise interventions paradigm is an innovative approach to interventions that involve a set of rigorous techniques grounded in research to help people improve in a variety of life settings. Recently, it has been developed a wise intervention aimed at improving adolescents' daily dietary choices. This intervention, called the values alignment intervention, focused on the role of marketing on the behavior of children and adolescents who are exposed to a relentless barrage of marketing from the food industry. The values alignment intervention seeks to neutralize the positive emotional associations with junk food that marketing generates and presents the rejection of unhealthy foods in favor of healthy alternatives as a way to live up to two values that are important to adolescents: (1) the desire to be autonomous from adult control, and (2) the desire for social justice. In two randomized controlled trials, it has been demonstrated that the intervention reduced implicit positive associations with junk food and substantially improved dietary choices, especially in boys. In addition, there were significant differences in attitudinal variables related to healthy eating. These promising results suggest that reframing unhealthy eating as incompatible with important youth values could be a low-cost solution to produce changes in adolescent attitudes and dietary choices. Therefore, the general objective of this project is to adapt the values alignment intervention to improve obesity-related eating habits in Spanish adolescents and evaluates its effectiveness. It is therefore a highly innovative project with great potential for social impact in the field of health promotion.

A randomized controlled trial with two groups will be used. Randomization will be done by clusters, using the classroom as the unit. First, the schools will be selected according to their characteristics. Then, for each school and grade, half of the classrooms will be randomly assigned to the experimental condition (values alignment condition) and the other half to the active control condition (traditional educational intervention) in parallel for the duration of the study.

Allocation will be concealed to the participants and teachers. Assessment will be done online through self-reports.

1 hour wise intervention (based on a values alignment approach) consisting on several tasks (online and paper-based tasks) to be completed individually.

1 hour traditional educational intervention on nutrition and physical exercise. This will also include reading and writing exercises.

The intervention includes: (1) reading materials, such as recent journalistic works that expose the deceptive and manipulative marketing practices of food companies and the harmful effects of these practices on society, with particular emphasis on harm to young children and the economically disadvantaged. Stories from other young people will also be included in order to contribute to the perception of widespread outrage and to suggest how that outrage can be channeled into taking a stand against the injustice perpetrated by food companies by eating less unhealthy or healthier food; (2) writing exercises, such as a story with a brief statement of what the participants would tell a younger child about the ads; and (3) an interactive activity, called "Make It Real" in which they are shown pictures of food ads and allowed to write and draw about them, making whatever changes (e.g., crossing out and substituting words) they feel necessary to make the ad "real" (i.e., no longer misleading).

The educational intervention includes information on nutrition and physical exercise. It includes reading and writing exercises.

Change from baseline scores of healthy and unhealthy food intake using the questionnaire developed by Stok et al. (2015).

It consists of four items that ask frequency of consumption of healthy and unhealthy food. It provides an index of unhealthy eating. Five response categories are provided: "none", "1", "2", "3", "4", or "more than 4 per day".

Change from baseline scores of the alignment of healthy eating habits with the values of adolescents using a questionnaire developed from Bryan et al. (2019).

It consists of seven items that assess adolescents' interpretation of healthy eating as addressing social justice issues (4 items) and as an assertive behavior expressing autonomy and independence (3 items). Each item is scored 0-4 (0 = not true; 4 = extremely true), yielding a total between 0 and 28.

Change from baseline scores of the social attractiveness of healthy eating using a questionnaire developed by Bryan et al. (2019).

It consists of three items that assess social attractiveness of healthy eating. Each item is scored 0-4 (0 = not at all agree; 4 = totally agree), yielding a total between 0 and 12.

Inclusion Criteria: Informed consent by the adolescents and their parents. To be fluent in Spanish and/or Euskera. Exclusion Criteria: Lack of permission by parents and the adolescent. Lack of understanding of the instructions.

The study protocol and informed consent protocol will be published at clinicaltrials.org Data will be available at OSF when the results are published.

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