A School-Based Intervention to Prevent Disordered Eating in Middle School Students

The study was conducted with seventh-grade middle school students aged 12-13 years (n = 235) and their parents (n = 129). Classes were randomly assigned to the intervention (n = 138 students) and control (n = 97 students) groups. Before the intervention, the Eating Disorder Examination Questionnaire Short Parent Version was administered to parents, and one-day dietary records of their children were collected. The students completed the Numerical Rating Scale, Social Media Literacy Scale, Eating Attitudes Test-26 (EAT-26), Sociocultural Attitudes Towards Appearance Questionnaire-4-Revised, and Mediterranean Diet Quality Index, and their anthropometric measurements were taken.

The scales were administered to the intervention group before and after the intervention and at the 12-week follow-up, and to the control group at baseline and at the 12-week follow-up. The intervention group received a three-week educational program delivered once per week. Each weekly session consisted of two consecutive 40-minute class periods (80 minutes per week), for a total of six 40-minute class periods over three weeks. The control group continued their usual school curriculum with their teachers during the same period. In addition, parents of students in the intervention group received one 40-minute educational session.

• School-Based Disordered Eating Prevention Education Program (Behavioral): The intervention consisted of three student modules and one parent module. The first module focused on body image, body satisfaction, body acceptance, and the prevention of weight- and body-related peer bullying. It was delivered by a psychologist specializing in adolescent psychology and included scenarios, videos, and positive peer feedback activities. The second module addressed social media literacy, unrealistic appearance ideals, dieting myths, online information reliability, screen time, and family meals. The third module covered healthy and balanced nutrition, food groups, the balanced plate model, and physical activity, including a classroom-based plate activity. Previous session topics were briefly reviewed at the beginning of each module. Six weeks after the intervention, a 10-minute refresher session was delivered by the researcher, a dietitian. The parent session addressed eating disorders, their symptoms and risk factors, and healthy nutrition principles.

Primary outcomes

• Change in Eating Attitudes Test-26 (EAT-26) Score [Baseline, immediately post-intervention (intervention group only), and 12-week follow-up]: Eating attitudes were assessed using a 24-item version of the Eating Attitudes Test-26 (EAT-26). Total scores range from 0 to 72, with higher scores indicating a greater risk of disordered eating attitudes and behaviors.

Secondary outcomes

• Change in Eating Disorder Examination Questionnaire Short Parent Version (EDE-QS-P) Score [Baseline, immediately post-intervention (intervention group only), and 12-week follow-up]: Eating disorder symptoms in students were assessed from the parent perspective using the Eating Disorder Examination Questionnaire Short Parent Version (EDE-QS-P). Total scores range from 0 to 33, with higher scores indicating greater severity of eating disorder symptoms.
• Change in Body Satisfaction [Baseline, immediately post-intervention (intervention group only), and 12-week follow-up]: Body satisfaction was assessed using a Numerical Rating Scale (NRS), on which students rated their level of satisfaction with their body. The minimum possible score is 0 ("not at all satisfied"), and the maximum possible score is 10 ("very satisfied"). Higher scores indicate greater body satisfaction. Changes in body satisfaction scores were evaluated across the assessment time points.
• Change in Sociocultural Attitudes [Baseline, immediately post-intervention (intervention group only), and 12-week follow-up]: Sociocultural attitudes toward appearance were assessed using the Sociocultural Attitudes Towards Appearance Questionnaire-4 Revised (SATAQ-4R), which consists of 31 items across seven subscales assessing internalization of appearance ideals and perceived appearance-related pressures. Items are rated on a 5-point Likert scale. Possible subscale scores range from 4 to 20 for thinness/low body fat internalization and each perceived pressure subscale (family, peers, significant others, and media), from 5 to 25 for muscularity internalization, and from 6 to 30 for general attractiveness internalization. Higher subscale scores indicate greater internalization of sociocultural appearance ideals or greater perceived appearance-related pressure.
• Change in Social Media Literacy [Baseline, immediately post-intervention (intervention group only), and 12-week follow-up]: Social media literacy was assessed using the Information Awareness dimension of the Social Media Literacy Scale (SMOÖ). This dimension evaluates students' awareness and critical understanding of information encountered on social media. The minimum possible score is 3, and the maximum possible score is 15. Higher scores indicate greater information awareness in relation to social media content.
• Change in BMI-for-Age Z-Score [Baseline and 12-week follow-up]: BMI-for-age z-scores were calculated based on participants' measured body weight and height using age- and sex-specific reference standards. Changes in BMI-for-age z-scores were evaluated from baseline to the 12-week follow-up.
• Change in Waist Circumference [Baseline and 12-week follow-up]: Waist circumference was measured in centimeters (cm) using a non-stretchable measuring tape. Changes in waist circumference were evaluated from baseline to the 12-week follow-up.
• Change in Body Fat Percentage [Baseline and 12-week follow-up]: Body fat percentage was assessed using bioelectrical impedance analysis. Changes in body fat percentage were evaluated from baseline to the 12-week follow-up.
• Change in Diet Quality and Dietary Intake [Baseline and 12-week follow-up]: Diet quality was assessed using the Mediterranean Diet Quality Index for Children and Adolescents (KIDMED). Total KIDMED scores range from -4 to 12, with higher scores indicating greater adherence to the Mediterranean diet. Dietary intake was assessed using dietary records to estimate energy and nutrient intakes. Changes in diet quality and dietary intake were evaluated from baseline to the 12-week follow-up.

Sex: All, ages: 12 Years to 13 Years, accepts healthy volunteers

Inclusion Criteria:

* Enrolled in the seventh grade at the school where the study is conducted.
* Aged 11-13 years.

Exclusion Criteria:

* Having any health condition that would prevent the participant from completing the questionnaires.