Examining the Efficacy of Post-Primary Nutritional Education Interventions as a Preventative Measure for Diet-Related Diseases: A Scoping Review

Abstract

Globally, unhealthy dietary behaviours are consistently seen to significantly contribute to the burden caused by diet-related diseases (DRDs). This is particularly evident among adolescents, a demographic that are at a critical stage of development for lifelong eating habits. This study aims to map the efficacy of post-primary school-based nutritional education (NE) interventions in the modification of adolescent dietary behaviours. A scoping review methodology was implemented, following the Joanna Briggs Institute framework, and adhering to PRISMA-ScR guidelines. Peer-reviewed research from 2015 to 2024 was thoroughly searched using the PubMed and Scopus databases, with inclusion criteria centred on school-based NE interventions aimed at changing post-primary students’ eating habits. In total, 50 studies were selected for analysis, which were then further categorised into five key intervention approaches: knowledge and behaviour-focused programmes, DRD-specific interventions, gamified or interactive learning methods, peer-led or externally facilitated programmes, and school food environment modifications. The findings indicate that structured NE interventions, particularly those incorporating behavioural theories, show positive outcomes in enhancing adolescent dietary knowledge and self-efficacy. The gamified interventions and interactive approaches demonstrated high engagement among participants, but the success of long-term changes was varied. The interventions addressing DRDs, especially obesity, showed significant impacts when combining educational components with structural modifications to school food environments. Peer-led models improved relatability and participation rates but faced challenges in terms of standardisation and repeatability. While school-based NE interventions effectively improve adolescent nutritional knowledge and behaviours, future research should focus on long-term follow-up assessments to determine the sustainability of these changes. These findings offer valuable insights for educators designing curricula, policymakers developing school health strategies, and practitioners seeking to implement feasible, evidence-based nutrition programmes in diverse educational settings.

1. Introduction

1.1. Background

Unhealthy dietary behaviours are associated with a myriad of diseases and health complications. In spite of this, in many advanced economies, diet quality remains suboptimal, with only a small fraction of the population adhering to established dietary guidelines [1,2,3]. Unhealthy diets primarily consist of processed fast foods and high-sugar snacks, together with excessive consumption of red and processed meats [4,5,6]. Following this type of dietary pattern greatly increases the risk of obesity, alongside cardiovascular diseases, type 2 diabetes and many other diet-related diseases (DRDs) [4,7,8]. DRDs are a primary concern for the public health sector, with one in five deaths in adults globally being linked to an unhealthy diet [9,10,11]. Healthcare systems across the world face substantial financial burdens from these conditions while experiencing dramatic increases in both patient illness and death rates [12,13]. The World Health Organisation [14] reports that non-communicable diseases were linked to 75% of global non-pandemic-related deaths in 2021, while inadequate nutrition played a role in many of these fatal outcomes. Nutritional education (NE) and interventions are emerging as pivotal tools for successfully promoting healthier eating habits and could be implemented to reduce the incidence of DRDs [15,16,17]. School-based interventions in particular are theoretically grounded in behavioural change models such as the social cognitive theory (SCT), which emphasises observational learning and self-efficacy [18,19], and the theory of planned behaviour (TPB), which highlights the role of intention, attitude, and perceived behavioural control in guiding action [20,21]. These frameworks support the idea that adolescents, when placed in supportive school environments that foster knowledge, motivation, and skill-building, are more likely to adopt and maintain healthier behaviours [18,19,20,21]. It is also important to note that while the term “post-primary setting” is widely used in research to refer to education following the age of 11 or 12, there are international variations in how secondary education is structured. In some countries, secondary education does not begin until the age of 13 or 14. As such, for the purposes of this review, “post-primary” is used to broadly refer to educational contexts serving adolescents, typically between the ages of 12 to 18, to reflect this global variation.

1.2. Influencing Factors and Adolescent Dietary Habits

Adolescence is considered a critical stage for growth and development and can have massive implications for a person’s long-term health [22]. Research has shown that attitudes and behaviours developed in adolescence relating to dietary practices often continue into adulthood [23,24]. One recent study has shown that participants who established positive dietary habits and experiences during mid-adolescence were more likely to maintain a greater interest in following a healthier diet in adulthood, compared to those who did not [24]. If unhealthy eating habits, physical inactivity, and other weight-related issues become the norm from adolescence into early adulthood, young adults, and the future generations they influence as parents, will encounter an elevated risk and prevalence of DRDs [25]. Some of the more common eating habits held by adolescents today include skipping meals, frequent snacking, and dining out, often accompanied by a diet which lacks nutritious foods (fruits, vegetables, and whole grains) and is instead made up of processed foods and drinks high in saturated fats, salt, or added sugars [26,27]. Due to the impressionable nature of children, we must consider that there is a range of factors and influences that could encourage them to succumb to these behaviours.

Advertising campaigns which endorse unhealthy foods and market them to children and adolescents pose a substantial barrier to promoting healthy eating habits. Aggressive advertising, particularly through digital platforms, targets children with products high in sugar, fats, and salts, undermining NE efforts [28,29]. This exposure not only normalises poor dietary choices but also negatively impacts the efficacy of interventions to develop a solid foundation during formative years [30,31]. Socioeconomic factors also play a pivotal role in shaping dietary behaviours among adolescents. Food insecurity and limited access to affordable, nutritious food are prevalent in lower-income communities, resulting in a reliance on unhealthy food options [32,33]. Studies have shown that these disparities can correlate with higher rates of DRDs, emphasising the need for targeted NE interventions particularly aimed at the lower levels of the socioeconomic ladder [34,35]. Cultural influences also shape dietary behaviours by promoting specific food traditions, beliefs, and practices. In some cultures, diets high in carbohydrates or fats are common, and when consumed in excess, greatly contribute to the incidence of DRDs. Adolescents in cultures where large portions and fast food are common may adopt unhealthy habits such as frequent snacking, high fast-food intake, and low fruit and vegetable consumption [36,37].

1.3. The Role of NE in Adolescence

Focusing on adolescents through food literacy and skills-based food interventions is one possible way to instil lifelong healthy eating habits, ultimately reducing the burden of DRDs. At this age, there is typically an evolution from a largely parental-controlled diet to a more self-directed and peer-influenced dietary lifestyle [38,39]. During this period, young people generally assert independence in their dietary decisions and eating behaviours [39,40]. As a result, good NE during this developmental stage might prompt healthy eating behaviours, thereby mitigating subsequent health risks [41,42]. Effective NE programmes equip adolescents with the knowledge and skills necessary to make informed decisions about their diets, which is particularly important given the increasing exposure to unhealthy food options and conflicting dietary information through social media and peer influence [43,44]. Furthermore, these interventions provide a foundation for understanding the long-term consequences of dietary habits, reinforcing the importance of balanced nutrition in preventing the onset of DRDs and promoting overall well-being [45,46]. By encouraging young people to think critically about their food choices, these interventions might act as a deterrent from the allure of unhealthy eating patterns prevalent in adolescence. When grounded in behavioural change theory, these programmes can enhance adolescents’ confidence and motivation to adopt healthier eating patterns, thereby increasing the likelihood of lasting impact.

While the merits of NE are well-established, a thorough examination of intervention strategies specifically aimed at post-primary cohorts is yet to be explored. The primary aim of this paper was to conduct a scoping review of the literature pertaining to school-based food and NE programmes aimed at adolescents and in particular, those focused on altering dietary behaviours in this demographic. The secondary aim was to allow the researcher to comprehensively analyse current data, in order to provide a thorough overview of various intervention components and the outcomes they achieved and identify research gaps which can be further explored.

2. Materials and Methods

2.1. Review Protocol

A systematic scoping review was undertaken for this paper in accordance with the most recent guidance set out by the Joanna Briggs Institute [47], as it provides a comprehensive and well-established methodological framework specifically designed for scoping reviews. In accordance with the Joanna Briggs Institute methodology for scoping reviews, no formal quality appraisal of included studies was conducted, as the primary aim was to map the extent and nature of research activity rather than evaluate study quality. This framework ensures accuracy in identifying, selecting, and synthesising the relevant literature, and is particularly useful when exploring broad or emerging areas of research, such as post-primary food education interventions [48]. By adhering to these guidelines, the paper could systematically map central themes, identify gaps in the literature, and examine the extent and nature of the research available on the topic [48].

This paper employed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) checklist standards [49]. The PRISMA-ScR checklist is internationally recognised for enhancing transparency and consistency in reporting scoping reviews, ensuring that all relevant steps in the research process are documented clearly. This increases the reliability of the review’s findings and allows for easier replication by future researchers. The checklist which indicates compliance with the guidelines, is reported in

Table A1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) checklist.

SECTION	ITEM	PRISMA-ScR CHECKLIST ITEM	REPORTED ON PAGE #
TITLE
Title	1	Identify the report as a scoping review.	1
ABSTRACT
Structured summary	2	Provide a structured summary that includes (as applicable): background, objectives, eligibility criteria, sources of evidence, charting methods, results, and conclusions that relate to the review questions and objectives.	1
INTRODUCTION
Rationale	3	Describe the rationale for the review in the context of what is already known. Explain why the review questions/objectives lend themselves to a scoping review approach.	2–3
Objectives	4	Provide an explicit statement of the questions and objectives being addressed with reference to their key elements (e.g., population or participants, concepts, and context) or other relevant key elements used to conceptualize the review questions and/or objectives.	3
METHODS
Protocol and registration	5	Indicate whether a review protocol exists; state if and where it can be accessed (e.g., a Web address); and if available, provide registration information, including the registration number.	3
Eligibility criteria	6	Specify characteristics of the sources of evidence used as eligibility criteria (e.g., years considered, language, and publication status), and provide a rationale.	3–4
Information sources *	7	Describe all information sources in the search (e.g., databases with dates of coverage and contact with authors to identify additional sources), as well as the date the most recent search was executed.	4
Search	8	Present the full electronic search strategy for at least 1 database, including any limits used, such that it could be repeated.	4
Selection of sources of evidence †	9	State the process for selecting sources of evidence (i.e., screening and eligibility) included in the scoping review.	4–5
Data charting process ‡	10	Describe the methods of charting data from the included sources of evidence (e.g., calibrated forms or forms that have been tested by the team before their use, and whether data charting was done independently or in duplicate) and any processes for obtaining and confirming data from investigators.	5
Data items	11	List and define all variables for which data were sought and any assumptions and simplifications made.	5
Critical appraisal of individual sources of evidence §	12	If done, provide a rationale for conducting a critical appraisal of included sources of evidence; describe the methods used and how this information was used in any data synthesis (if appropriate).	N/A
Synthesis of results	13	Describe the methods of handling and summarizing the data that were charted.	5
RESULTS
Selection of sources of evidence	14	Give numbers of sources of evidence screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally using a flow diagram.	5–6
Characteristics of sources of evidence	15	For each source of evidence, present characteristics for which data were charted and provide the citations.	6–15
Critical appraisal within sources of evidence	16	If done, present data on critical appraisal of included sources of evidence (see item 12).	N/A
Results of individual sources of evidence	17	For each included source of evidence, present the relevant data that were charted that relate to the review questions and objectives.	6–18
Synthesis of results	18	Summarize and/or present the charting results as they relate to the review questions and objectives.	6–18
DISCUSSION
Summary of evidence	19	Summarize the main results (including an overview of concepts, themes, and types of evidence available), link to the review questions and objectives, and consider the relevance to key groups.	18–21
Limitations	20	Discuss the limitations of the scoping review process.	21
Conclusions	21	Provide a general interpretation of the results with respect to the review questions and objectives, as well as potential implications and/or next steps.	21
FUNDING
Funding	22	Describe sources of funding for the included sources of evidence, as well as sources of funding for the scoping review. Describe the role of the funders of the scoping review.	21

* Where sources of evidence (see second footnote) are compiled from, such as bibliographic databases, social media platforms, and Web sites. † A more inclusive/heterogeneous term used to account for the different types of evidence or data sources (e.g., quantitative and/or qualitative research, expert opinion, and policy documents) that may be eligible in a scoping review as opposed to only studies. This is not to be confused with information sources (see first footnote). ‡ The frameworks by Arksey and O’Malley (6) and Levac and colleagues (7) and the JBI guidance (4, 5) refer to the process of data extraction in a scoping review as data charting. § The process of systematically examining research evidence to assess its validity, results, and relevance before using it to inform a decision. This term is used for items 12 and 19 instead of "risk of bias" (which is more applicable to systematic reviews of interventions) to include and acknowledge the various sources of evidence that may be used in a scoping review (e.g., quantitative and/or qualitative research, expert opinion, and policy document).

of Appendix A. Although no external registration was completed, an internal protocol was developed to guide the review process, such as eligibility criteria and charting strategy. The researchers acknowledge that the absence of protocol registration limits external reproducibility and transparency.

2.2. Eligibility Criteria

The eligibility criteria outline the specific parameters that determine the publications which would be included or excluded from the scoping review [50]. To be included in the review, the articles must have met pre-determined inclusion criteria, which were English-language, full-text, peer-reviewed journal papers published from 2015 to March 2024 evaluating educational interventions or initiatives implemented in post-primary settings. The decision to focus on this time frame is consistent with other systematic studies examining educational nutrition-focused interventions [51,52], allowing the review to capture the most recent and relevant literature. Limiting the scope to post-primary settings aligns with the research focus on secondary education, ensuring that the interventions target the relevant age group for the paper’s goals. Additionally, the emphasis on evaluating the effectiveness and suitability of educational interventions is crucial, as these criteria provide direct insight into the success and applicability of the interventions in preventing DRDs. For the purpose of this review, “educational interventions” are defined as structured programmes or strategies delivered in school settings with the aim of improving adolescents’ nutritional knowledge, dietary attitudes, and/or eating behaviours. These include, but are not limited to, curriculum-integrated lessons, interactive workshops, gamified learning modules, peer-led sessions, and environment-focused education, such as canteen adjustments supported by educational messaging.

Studies that were non-peer-reviewed literature, dissertations, conference abstracts, and publications not available in English were excluded. Limiting to English-language publications is a practical decision, as translating studies could introduce bias or inaccuracies, though the researcher acknowledges that this may limit some potentially relevant findings. Interventions which failed to involve a post-primary or equivalent cohort, or which did not involve educational interventions related to diet/health-related diseases, were also not considered for inclusion. This ensured that the scope of the review remained focused and relevant, specifically targeting interventions applicable to this paper’s primary objectives [53].

2.3. Search and Information Sources

Articles from two scientific databases (PubMed and Scopus) were retrieved using the keywords and MeSH Terms seen in

Table 1. Search terms derived from associated concepts.

Concept	Search Term
Educational intervention	“Education* program*” OR “Food Education” OR “Health education” OR “Cooking skills” OR “nutrition education” OR “Intervention strategies*” OR “School-based intervention*”
	AND
Post-primary cohort	“Secondary School*” OR “Post primary” OR “High School” OR “Middle school”
	AND
Diet-related disease	“Diet* disease*” OR “diet-related disease*” OR “Nutri* related disease*”

the asterisk (*) represents any group of characters, including no character in order to broaden search terms.

utilising logical operators AND or OR. These two databases were chosen as they are the ones most frequently used from a food and education perspective [54,55]. The search was conducted in March 2024, and the search results were transferred into Rayyan software (https://www.rayyan.ai).

2.4. Selection of Sources of Evidence

All articles collected were extracted to the Rayyan software, which identified duplicates that were then screened and removed. Rayyan is widely recognised for its ability to streamline the systematic review process, especially in terms of screening and managing large volumes of references [56]. Its duplicate identification feature reduces manual labour and ensures efficiency by automatically flagging multiple entries of the same publication, maintaining the integrity of the dataset.

The decided-upon inclusion and exclusion criteria were used by the primary researcher (KM) to screen both the titles and abstracts of the remaining articles. This step ensures concise study selection of relevant studies before moving on to full-text analysis, providing an efficient method to refine the dataset. Two secondary researchers (AM and LM) also screened all titles and abstracts, adding an extra layer of reliability to the process. Using two reviewers helps minimise bias and errors, which aligns with best practices for systematic reviews [57]. All researchers discussed and deliberated on any conflicting decisions and came to a consensus on whether to include each journal, based on the inclusion and exclusion criteria, to prevent bias.

2.5. Data Charting Process and Data Items

The included studies were descriptively analysed by a researcher (KM) using a customised electronic data sheet using the following headings: author, publication year, title, country, study design, objective, intervention details, outcomes measured, duration, and results (

Table 2. Data extracted from included articles.

Author	Title	Country	Study Design	Study Objective	Intervention Detail	Evaluation Process/Outcomes Measured	Duration	Results
Al Haroni et al., 2024 [58]	Effectiveness of education intervention, with regards to physical activity level and a healthy diet, among Middle Eastern adolescents in Malaysia: A study protocol for a randomised control trial, based on a health belief model	Malaysia	Randomised controlled Trial	To improve knowledge, attitude, and practices about body weight, nutrition, and physical activity among Middle Eastern adolescents	Integrated health education intervention. 6 fortnightly sessions (45 min/session) over 6 weeks. Target group: 13–14-year-olds in Arabic secondary schools in Malaysia.	Anthropometric measurements: -Knowledge, attitude, and practices; -Physical activity and sedentary behaviour; -Food assessment and eating attitudes; -Baseline, post-intervention, and 2-month follow-up.	2 months total (6-week intervention plus follow-up)	Data collection ongoing. Expected to improve physical activity, diet adherence, and reduce NCD risk behaviours.
Aresi et al., 2023 [59]	Process Evaluation of Food Game: A Gamified School-Based Intervention to Promote Healthier and More Sustainable Dietary Choices	Italy	Mixed methods process evaluation	To evaluate and gather information on the food game	Offline and online competitions to design and communicate products and ideas that promote health and sustainability.	Change in perceptions of students. Teacher experience with the programme.	1 year	Acceptable and engaging intervention. No sufficient evidence to show it promotes healthier/more sustainable behaviours.
Miller et al., 2023 [60]	Rethinking Adolescent School Nutrition Education Through a Food Systems Lens	Australia	Mixed methods case study	To explore food systems as an alternative approach to engage students in nutrition education	Played a food systems computer game (“Farm to Fork”). Group discussions on food systems, food production, and food waste.	Key themes identified in group discussions about food production, food waste, and healthy food choices. Request for additional content on food production, costs, processing, and accessing local produce.	1 year	Students reported crop growth, food production, food waste, and food systems knowledge as game outcomes. Requested more content on food production, handling, and local produce. Preferred experiential learning activities.
Rizvi et al., 2022 [61]	Outcome of structured health education intervention for obesity-risk reduction among junior high school students: Stratified cluster randomised controlled trial (RCT) in South India	India	Randomised controlled trial	Assess health education’s impact on obesity-related KAP in adolescents and estimate post-intervention changes in BMI and body fat %	Presentation including motivational pictures, phrases and videos. Reinforced with posters and worksheets.	Questionnaire to assess KAP towards diet and physical activity over 3 visits.	2 years	Intervention group had better knowledge regarding diet and health; however, knowledge improved in both groups.
Angeli et al., 2022 [62]	Implementation and Evaluation of a School-Based Educational Program Targeting Healthy Diet and Exercise (DIEX) for Greek High School Students	Greece	Quasi-experimental design	To assess the effectiveness of the DIEX programme in improving adolescents’ knowledge and behaviour regarding healthy diet and exercise	DIEX programme based on the theory of planned behaviour (TPB), life skills training, and digital elements. 10 sessions, 1 h each, implemented by schoolteachers. Topics included behaviour-modification, goal setting, stress management, problem-solving, and cognitive restructuring.	Changes in students’ knowledge and behaviour regarding healthy eating. Attitudes and satisfaction towards the DIEX program. Perceived impact on subjective norms, intentions, and perceived behavioural control (PBC).	10 sessions (1 h each)	Significant improvements in knowledge and behaviour related to a healthy diet. Positive attitudes and high satisfaction with the program. No significant impact on subjective norms, intentions, or perceived behavioural control. Programme successfully changed students’ behaviour related to healthier diets.
Said et al., 2022 [63]	Effect Evaluation of Sahtak bi Sahnak, a Lebanese Secondary School-Based Nutrition Intervention: A Cluster Randomised Trial	Lebanon	Cluster randomised controlled trial	To evaluate the effectiveness of Sahtak bi Sahnak on dietary knowledge and adherence to dietary guidelines in Lebanese adolescents	Sahtak bi Sahnak: educational school-based intervention. Aimed at improving dietary knowledge, adherence to nutritional guidelines, and preventing obesity. Intervention designed using the intervention mapping framework.	Dietary knowledge and adherence to dietary guidelines measured at baseline and post-intervention using validated questionnaires.	2 months (7 educational sessions, covering 11 lessons: 20–40 min each)	Improved dietary knowledge. Increased intake of healthy foods. Decreased intake of unhealthy foods.
LeBlanc et al., 2022 [64]	An elective high school cooking course improves students’ cooking and food skills: a quasi-experimental study	Canada	Quasi-experimental design	To evaluate the effectiveness of the Professional Cooking (PC) course on cooking skills, food behaviours, and vegetable and fruit consumption	Teaches cooking techniques, food safety, and recipe following.	Cooking skills, food and cooking skills, vegetable and fruit consumption, and eating behaviours measured using pre- and post-questionnaires.	18 weeks	Significant improvements in cooking skills for students in the PC course. No significant impact on vegetable and fruit consumption or other eating behaviours.
Gowland-Ella et al., 2022 [65]	Thirsty? Choose Water! Encouraging Secondary School Students to choose water over sugary drinks. A descriptive analysis of intervention components	Australia	Randomised controlled trial	To evaluate the effectiveness of a behavioural intervention (BI) and a chilled water station (CWS) on encouraging students to choose water over sugary drinks	Behavioural intervention (BI): delivered through classroom lessons, school promotions, and vaccination clinic. Chilled water station (CWS): one CWS installed per school.	Changes in student knowledge about sugary drinks (SSBs) and hydration, daily SSB consumption, water bottle usage, and water consumption measured via student surveys.	3 time points (baseline, post-intervention, follow-up) (over the course of 1 year)	The BI led to improved student knowledge about sugary drinks and dehydration, along with reduced sugary drink consumption. The CWS resulted in increased water consumption and higher rates of students carrying water bottles to school.
Schapiro et al., 2021 [66]	Impact on Healthy Behaviors of Group Obesity Management Visits in Middle School Health Centers	USA	Mixed-methods community-based participatory pilot study	To examine the feasibility and preliminary efficacy of group obesity management visits through school health centres	Group obesity management visits were implemented through three school-based health centres serving primarily Latinx and African American youth. The intervention included group visits with focus on diet, exercise, and stress-reduction mindfulness exercises.	Changes in soda consumption, exercise days, and social support. Knowledge and self-efficacy related to healthy eating. Student focus group feedback on programme activities.	Pre- and post-surveys, focus groups conducted after the intervention and 18 months later	Significant decrease in soda consumption. Increased support from classmates and more exercise days. Positive feedback from students about cooking, tasting, and shopping activities, family involvement and mindfulness techniques. Young people suggested programme refinements, such as better access to healthy foods.
Ooi et al., 2021 [67]	A trial of a six-month sugar-sweetened beverage intervention in secondary schools from a socio-economically disadvantaged region in Australia	Australia	Pilot cluster randomised controlled trial	To assess the effectiveness of a multi-component school-based intervention on reducing daily SSB consumption and energy from SSBs in adolescents	The intervention included strategies based on the WHO’s Health Promoting School (HPS) framework, targeting school SSB availability, pricing, health-related self-efficacy, peer influence, and family factors. It involved behavioural change techniques to improve students’ capability and motivation to reduce SSB intake.	Primary outcomes: overall daily SSB consumption (mL), daily percentage of energy from SSBs. Secondary outcomes: SSB consumption at school, daily energy intake (kJ), student BMI z-scores.	Pre- and post-surveys, food frequency questionnaires, BMI measurement 6 months	There were no significant differences between the intervention and control schools for SSB consumption, energy intake, or BMI. Small reductions in SSB consumption and energy from SSBs were observed within the intervention group but were not statistically significant when compared to the control group. The findings suggest the need for more robust implementation strategies and potentially extending the intervention duration.
Huitink et al., 2021 [68]	The Healthy Supermarket Coach: Effects of a Nutrition Peer-Education Intervention in Dutch Supermarkets Involving Adolescents With a Lower Education Level	Netherlands	Quasi-experimental pre–post design with a comparison school	To investigate the impact of a supermarket-based nutrition peer education intervention on adolescents’ nutritional knowledge and attitudes towards healthy eating	The intervention was held in supermarkets near schools and involved peer education. It aimed to improve adolescents’ nutritional knowledge and attitudes toward healthy eating, particularly targeting those with lower education levels.	Primary outcomes: nutritional knowledge, attitudes toward healthy eating. Secondary outcomes: self-reported dietary behaviours during school hours, food purchases.	Pre- and post-intervention surveys, comparison of intervention and control schools 3 months	Statistically significant improvements in nutritional knowledge and attitudes towards healthy eating were found in the intervention group compared to the comparison school. The intervention was well received by participants, and most adolescents reported purchasing food from supermarkets during school hours.
Selamat et al., 2021 [69]	Fruit and vegetable intake among overweight and obese school children: A cluster randomised control trial	Malaysia	Cluster randomised controlled trial	To evaluate the effect of a nutrition education intervention (NEI) based on the trans-theoretical model (TTM) on fruit and vegetable intake among overweight and obese secondary school children	The intervention (MyBFF@school) included 24 weeks of NEI with 40–60 min sessions every two weeks. The Nutrition Education Module (NEM) covered five main topics: body weight, healthy eating, smart shopping, and more, focusing on fruit and vegetable intake. The sessions were delivered by trained personnel using interactive and practical methods.	Primary outcome: stages of change for fruit and vegetable intake (action, maintenance, etc.). Secondary outcome: changes in the percentage of children with adequate fruit and vegetable intake.	24 weeks for intervention group, with 6-month follow-up	No significant differences in stages of change between the intervention and control groups, but both showed a slight reduction in the maintenance stage. The intervention group saw a significant increase in adequate fruit and vegetable intake (from 17.8% to 28%), while the control group showed a smaller increase (from 20.6% to 26.6%). Significant increases in intake were observed in the intervention group at the pre-action and action stages.
Orta et al., 2021 [70]	Bridging the GAP: Leveraging Partnerships to Bring Quality Nutrition Education to the Gardening Apprenticeship Program	USA	Programme evaluation (non-RCT)	To assess the impact of a yearlong after-school intervention combining gardening, nutrition education, and hands-on cooking demonstrations to address food insecurity and improve health behaviours in adolescents	The intervention integrated hands-on cooking lessons with nutrition education in the Gardening Apprenticeship Program (GAP). The programme involved garden-based activities teaching food and environmental justice, alongside nutrition lessons from the Nourish curriculum. Each lesson included participatory cooking demonstrations.	Outcomes: participants’ knowledge of fruits and vegetables, food traditions, and influences on food choices. Specific lessons covered topics such as food labels, healthy drinks, and MyPlate. Programme success was assessed via pre- and post-programme evaluation of students’ attitudes and knowledge.	16 weeks of nutrition education with bi-monthly sessions, part of a yearlong intervention	The programme successfully engaged 12 high school students, enhancing their knowledge of nutrition and improving their skills in cooking healthy meals. Participants demonstrated increased knowledge and confidence in preparing healthy meals and were better able to identify the benefits of fruits and vegetables.
Berger et al., 2021 [71]	The Impact of a Short-term Intervention on Adolescent Eating Habits and Nutritional Knowledge	Israel	Prospective questionnaire-based study	To evaluate the effects of a school-based intervention on adolescents’ nutritional knowledge, eating habits, and physical activity	The intervention included the installation of vending machines with milk products, two nutrition lectures on age-appropriate nutrition and calcium, and one active sports day.	Outcomes: changes in eating habits (e.g., breakfast consumption, food purchasing habits), calcium knowledge, milk consumption, and physical activity levels.	One academic year (September 2014 to September 2015)	A significant increase in students eating breakfast. A decrease in the purchase of food at school. No significant changes were observed in milk consumption, vegetable consumption, knowledge about calcium, or physical activity.
Ibeanu et al., 2020 [72]	Evidence-based strategy for prevention of hidden hunger among adolescents in a suburb of Nigeria	Nigeria	Quasi-experimental, pretest and post-test	To evaluate the impact of a 14-page nutrition education aid on adolescents’ knowledge of micronutrients and their food choices	The intervention involved a 14-page locally developed nutrition education aid, which included nutrition facts, pictures of micronutrient-rich foods, and computer graphics. The intervention aimed to improve knowledge on food sources, functions, and deficiencies in micronutrients such as vitamin C, folic acid, iron, calcium, and zinc.	Pre- and post-intervention knowledge of nutrition and food choices; consumption of micronutrient-rich foods before and after the intervention.	6 months (September 2016–July 2017)	Post-intervention, there was a significant improvement in nutrition knowledge, particularly regarding general nutrition and food sources of nutrients. Additionally, there was an increase in the daily consumption of micronutrient-rich foods such as meat, mango, watermelon, carrot, and leafy vegetables, while the proportion of students who rarely consumed these foods decreased.
Shen et al., 2020 [73]	The smartphone-assisted intervention improved perception of nutritional status among middle school students	China	Parallel-group controlled trial (non-randomised)	To examine the effectiveness of a smartphone-assisted intervention on improving students’ and parents’ perception of students’ nutritional status	There were three components: health education sessions for students and parents, regular monitoring of students’ weight, and providing feedback through a smartphone application. Schools in the control group continued their usual practices.	Primary outcomes measured were the students’ and parents’ accurate perceptions of students’ nutritional status (underweight, normal weight, overweight, obese).	3 months	The percentage of students in the intervention group who accurately perceived their nutritional status increased, while the control group showed a decrease. However, the intervention did not significantly improve parental perception of students’ nutritional status.
Westfall et al., 2020 [74]	Exploring the Relationship Between MyPlate Knowledge, Perceived Diet Quality, and Healthy Eating Behaviors Among Adolescents	USA	Secondary analysis of cross-sectional data	To evaluate middle school students’ knowledge of MyPlate nutrition messages and its association with dietary intake and perceived diet quality	The study assessed students’ knowledge of MyPlate using three questions about portion sizes (fruits and vegetables, grains, proteins). It also used a brief food frequency questionnaire to assess intake of various foods and beverages.	The study measured MyPlate knowledge, intake of fruits, vegetables, sweets, salty snacks, fast food, and sugar-sweetened beverages (SSBs), as well as students’ self-rated diet quality.	1 academic year (eighth grade)	MyPlate Knowledge: Only 11% of the students correctly answered all questions related to MyPlate portion sizes. Dietary Intake: MyPlate knowledge was associated with a reduced likelihood of consuming sugar-sweetened beverages (SSBs), but it was also linked to higher consumption of sweets. There was no significant impact on the intake of fruits, vegetables, salty snacks, or students’ self-perceived diet quality.
Jeihooni et al., 2019 [75]	Application of PRECEDE model in education of nutrition and physical activities in obesity and overweight female high school students	Iran	Quasi-experimental study	To assess the impact of an educational intervention based on the PRECEDE model on the nutrition and physical activity behaviours, and weight/BMI of overweight and obese female high school students	Educational intervention based on the PRECEDE model, delivered through 10 sessions (50–55 min each) focusing on nutrition, physical activity, and behaviour change.	Questionnaire to assess knowledge, attitude, self-efficacy, enabling and reinforcing factors, physical and nutrition performance, weight, and BMI.	3 months	Significant improvements in knowledge, attitude, self-efficacy, and physical/nutritional behaviours were observed in the experimental group. A reduction in weight and BMI was also noted in the experimental group, with no changes in the control group.
Salwa et al., 2019 [76]	Towards reducing behavioral risk factors of non-communicable diseases among adolescents: Protocol for a school-based health education program in Bangladesh	Bangladesh	Before–after design intervention study	To implement and evaluate a behaviour change intervention aimed at reducing behavioural risk factors of non-communicable diseases (NCDs) among adolescents in Bangladesh	Health promotion sessions based on motivational interviewing and social cognitive theory, delivered in groups of up to 25 students by trained facilitators.	Knowledge, attitude, and practices (KAPs) related to NCDs were assessed before and after the intervention using a questionnaire.	3 months	Results yet to be collected. Expected outcomes include increased awareness and behaviour change regarding NCD risk factors, with a focus on cost-effectiveness and group delivery.
Soares et al., 2019 [77]	Impact of a playful booklet about diabetes and obesity on high school students in Campinas, Brazil	Brazil	Pretest–post-test design	To evaluate the efficacy of a playful educational booklet focused on diabetes and obesity for high school students	A playful educational booklet with illustrations, games, and activities about diabetes and obesity. The booklet includes a range of activities from simple games to more complex knowledge-based tasks.	Student performance on a 10-question test was measured before and after using the booklet. The number of correct answers for each question was tracked.	1 h (booklet completion time)	Significant improvement in quiz performance after using the booklet. The percentage of correct answers increased in 7 out of 10 questions (p < 0.05). The greatest improvements were in questions 5 (36%), 8 (19%), and 6 (15%).
Fernandez-Jimenez et al., 2019 [78]	Rationale and design of the school-based SI! Program to face obesity and promote health among Spanish adolescents: A cluster-randomized controlled trial	Spain	Cluster-randomized controlled trial	To evaluate the impact of the SI! Programme on adolescent lifestyle behaviours and health parameters.	The intervention involved a multilevel, multicomponent school-based health-promotion intervention targeting adolescents aged 12–16 years. It includes a curriculum-based educational programme over 2 or 4 academic years.	Primary endpoint: change in composite Ideal Cardiovascular Health (ICH) score (BMI, dietary habits, physical activity, smoking, blood pressure, cholesterol, glucose) at 2-year and 4-year follow-ups. Secondary endpoints: changes in ICH subcomponents, Fuster–BEWAT health scale, adiposity markers, polyphenol and carotenoid intake, and emotion management.	2–4 years	Results yet to be collected.
McSweeney et al., 2019 [79]	The ‘voice’ of key stakeholders in a school food and drink intervention in two secondary schools in NE England: Findings from a feasibility study	United Kingdom	Qualitative study using focus groups and interviews	To explore perceptions of school food provision and a food architecture intervention among pupils and staff	The intervention involved rearranging the placement of food items: fruit placed in front of cakes/cookies, and water positioned at eye level.	Thematic analysis of pupil focus groups (n = 4) and staff interviews (n = 8); assessed dining practices, food choices, health awareness, and intervention knowledge.	Not specified	Pupils are aware of healthy options but often chose less healthy ones; structural changes improved the visibility and convenience of healthier choices, but mixed messages and food availability limited effectiveness.
Ostrowski et al., 2019 [80]	Demographics and anthropometrics impact benefits of health intervention: data from the Reduce Obesity and Diabetes Project	USA	Quasi-experimental, school-based intervention	To evaluate the efficacy of a 4-month health, nutrition, and exercise intervention on body fat in middle school students	Included a 12-session classroom-based health and nutrition programme incorporated into regular curriculum; optional exercise intervention offered.	Height, weight, waist circumference, BMI, and body composition measured pre- and post-intervention; subgroup analysis based on demographic and anthropometric factors.	4 months	Significant reductions in adiposity indices (BMI z-scores, body fat %, waist circumference); greater effects in males, obese students, and South Asians.
Askelson et al., 2018 [81]	Actively Involving Middle School Students in the Implementation of a Pilot of a Behavioural Economics–Based Lunchroom Intervention in Rural Schools	USA	Pilot study with multicomponent evaluation	To improve the lunchroom environment and empower food service staff to encourage healthy eating behaviours among middle school students	The intervention involved changes to the lunchroom environment using behavioural economics principles, communication training for food service staff, and food service staff cues to encourage healthy food choices.	Lunchroom assessments, surveys, production records, and interviews with food service directors and staff.	1 academic year	Five schools showed improvement in lunchroom assessment scores, and four schools increased the production of healthy food servings. Food service directors reported the intervention as feasible and well received.
Saez et al., 2018 [82]	Using facilitator-receiver peer dyads matched according to socioeconomic status to promote behaviour change in overweight adolescents: A feasibility study	France	Feasibility study (embedded within larger trial)	To evaluate the feasibility of a peer intervention promoting healthy eating and physical activity, targeting less-advantaged overweight adolescents	Peer facilitators, selected according to socioeconomic status, were trained to organize weight-control activities for peer receivers.	Primary: demand, acceptability, implementation, and practicality of the intervention. Secondary: socio-demographic and health characteristics; participant feedback on the experience.	1 year (larger study: 3 years)	Participation was higher when asked by peers (51.2% discordant pairs, p < 0.02). Participants (mostly girls, mean age 16) reported positive experiences, especially regarding social support.
Heo et al., 2018 [83]	Effective nationwide school-based participatory extramural program on adolescent body mass index, health knowledge and behaviors	USA	Quasi-experimental (pre-post comparison)	To evaluate the effectiveness of the HealthCorps programme on BMI z-scores, obesity rates, health knowledge, and behaviours among high school students	HealthCorps provided weekly or bi-weekly classroom lessons and after-school activities focusing on nutrition, physical activity, sleep, breakfast intake, and mental resilience.	Primary: changes in BMI z-scores. Secondary: changes in health knowledge and behaviours (fruit/vegetable intake, physical activity).	1 academic year	Significant decrease in BMI z-scores for overweight/obese and obese female students in the HealthCorps group. HealthCorps students showed significant increases in health knowledge and positive behaviour changes compared to the comparison group.
Patton-Lopez et al., 2018 [84]	Changes in sport nutrition knowledge, attitudes/beliefs and behaviors following a two-year sport nutrition education and life-skills intervention among high school soccer players	USA	Pre-post design (3-time assessments)	To evaluate the impact of a sport nutrition education and life-skills intervention on sport nutrition knowledge (SNK), attitudes/beliefs, and dietary behaviours among high school soccer players.	The WAVE programme included face-to-face sports, nutrition lessons, experiential learning, and team-building workshops (TBWs) focusing on nutrition and life skills such as meal planning, shopping on a budget, and food preparation.	Primary: changes in SNK scores, attitudes/beliefs, and dietary behaviours (breakfast, lunch consumption, eating for performance).	2 years	Significant improvements in SNK scores, especially in female athletes. IG players were more likely to report eating for performance and showed increased lunch consumption. The intervention also increased awareness of athletes’ nutritional needs compared to non-athletes.
Ahmadi et al., 2018 [85]	The effect of a social cognitive theory-based intervention on fast food consumption among students	Iran	Quasi-experimental (pre-post comparison)	To determine the effect of a social cognitive theory (SCT)-based intervention on fast food consumption among students	The intervention consisted of 4 sessions: defining fast food and its detriments, discussing value expectations (health risks), and improving self-efficacy to replace fast foods with healthier options.	Primary: changes in fast food consumption, self-efficacy, knowledge, and outcome expectations. Pre- and post-survey 3 months after intervention.	4 sessions (conducted within a short period)	Significant reduction in fast food consumption in the intervention group (p < 0.001). Improved self-efficacy, knowledge, and outcome expectancy in the intervention group. The control group showed no significant changes. The intervention group had significantly better scores in fast food consumption, knowledge, self-efficacy, and outcome expectancy compared to the control group.
Hashemzadeh et al., 2018 [86]	The effect of nutrition education course on awareness of obese and overweight female 1st-year High School students of Isfahan based on transtheoretical model of behavioral change	Iran	Semi-empirical (pretest-post-test with control and experimental groups)	To investigate the effects of a nutrition education course on the awareness of female 1st-year high school students based on the transtheoretical model (TTM) of behavioural change	Sessions every 2 weeks, with one brochure and 3 educational messages each week for the experimental group.	Pre- and post-intervention surveys using the following: Nutrition Awareness Questionnaire (15 items); Stages of Change Questionnaire. Statistical analysis: Independent t-test and Mann–Whitney test.	2 months	Significant improvement in nutrition awareness scores and progression to higher stages of change in the experimental group. The control group showed no significant changes. The intervention was effective in improving students’ awareness and behavioural stages related to nutrition.
Partida et al., 2018 [87]	Attitudes toward nutrition and dietary habits and effectiveness of nutrition education in active adolescents in a private school setting: A pilot study	USA	Pilot survey study	To investigate nutrition knowledge, attitudes, and beliefs about nutrition, exercise, and dietary habits of active adolescents	Three-part nutrition education intervention: -2 sessions by a registered dietitian in the classroom for middle school and high school students; -Educational posters; -Social media.	Surveys before and after intervention: -General and sport nutrition knowledge; -Dietary habits; -Attitudes toward nutrition education; -Self-reported exercise and sports participation.	Approx. 1 month	Most students expressed a desire to learn more about nutrition. The most effective delivery method was classroom lectures. Educational posters and social media were ineffective. Significant increase in knowledge about protein and exercise. Need for improvement in both general and sports nutrition knowledge.
Rabiei et al., 2017 [88]	Evaluation of the effectiveness of nutritional education based on the health belief model on self-esteem and BMI of overweight and at risk of overweight adolescent girls	Iran	Randomized controlled trial	To determine the effectiveness of nutrition education based on the health belief model (HBM) on self-esteem and BMI of overweight and at-risk adolescent girls	Health belief model-based intervention: -6 sessions (60 min each) focusing on overweight prevention. Topics: perceived susceptibility, severity, benefits, self-efficacy. Educational materials: lectures, Q&A, slides, booklets.	Pre- and post-intervention evaluations: -Knowledge: based on HBM structures; -Self-esteem: assessed via self-report; -BMI: measured by standardized tools; -Perceived susceptibility, severity, benefits, and self-efficacy: questionnaire scores.	3 months	Significant improvements in knowledge, perceived susceptibility, perceived severity, perceived benefits, and self-esteem in the intervention group. BMI significantly decreased in the intervention group but not in the control group. Positive long-term effects on knowledge and behaviour were observed.
Park et al., 2017 [89]	Stroke awareness in Korean high school students	South Korea	Pretest and post-test intervention study	To investigate the basic knowledge of Korean adolescents about stroke and evaluate the improvement after an educational lecture	Stroke education program: 50-min lecture on stroke: risk factors, symptoms, diagnosis, and management. Emphasised modifiable risk factors such as hypertension, diabetes, smoking, etc.	Pre-E, Post-E1, Post-E2 questionnaire: -Knowledge assessment on stroke risk factors, symptoms, and management; -Performance comparison on Pre-E, Post-E1, and Post-E2 tests; -Difference in performance for students who reported paying attention.	2 weeks	Significant improvement in stroke knowledge immediately after the lecture and at 2-week follow-up (p < 0.001). The students who paid attention during the lecture showed greater improvement in knowledge. The study supports incorporating stroke education into school curricula to reduce stroke risk behaviours in adolescents.
Schuh et al., 2017 [90]	Healthy school, happy school: Design and protocol for a randomized clinical trial designed to prevent weight gain in children	Brazil	Cluster-randomised parallel two-arm study	To evaluate the effectiveness of an intervention designed to improve knowledge of food choices and lifestyle in children and adolescents	Intervention activities: -Monthly activities in school’s multimedia room or sports court focusing on the following: -Nutritional education, physical activity, and lifestyle changes. -Control group receives usual school recommendations.	Primary outcomes: -Anthropometric measures (BMI percentiles); -Physical activity levels (International Physical Activity Questionnaire). Secondary outcomes: -Healthy eating behaviours, preferences for fruits/vegetables, increased physical activity, reduced sedentary behaviour.	Ongoing	Results not collected. Expected Outcomes: Increased consumption of fresh foods. Decreased consumption of sugary/processed foods. Reduced sedentary behaviour. The goal is to equip children with knowledge to make healthier choices for a better future.
Rogers et al., 2017 [91]	Top 10 Lessons Learned from Project Healthy Schools	USA	Non-randomized, observational study	To evaluate the effectiveness of Project Healthy Schools (PHSs) on improving childhood obesity and associated cardiovascular risk factors	Project Healthy Schools (PHSs): a school-based programme focusing on health education and environmental changes to promote healthy lifestyle choices in middle school students. -10 educational sessions (20–45 min each) covering topics such as healthy eating, physical activity, and reducing sedentary behaviour. -Environmental changes, such as providing healthier food and beverage options in schools.	Primary outcome: -Physiologic changes (e.g., lipid levels). Secondary outcome: -Health behaviours (e.g., diet, physical activity).	N/A	Improved Health Outcomes: Significant improvements in physiological measures (e.g., lipid profiles) and health behaviours (e.g., increased physical activity, healthier eating). Behavioural Changes: Students consumed healthier foods, engaged in more physical activity, and reduced screen time. Impact of Environmental Changes: The availability of healthier food and beverage options in schools supported these positive changes.
Meseri et al., 2017 [92]	School based multifaceted nutrition intervention decreased obesity in a high school: An intervention study from Turkey	Turkey	Interventional study	Assess nutritional knowledge, behaviours, and obesity status among high school students before and after interventions	Multifaceted nutrition and physical activity interventions, including lessons, changes to food environment, and support for PA.	BMI percentiles for obesity status, nutritional knowledge (10 multiple-choice questions), and behaviours via a nutrition score (scale 1–10).	1 year	Improved nutritional knowledge and behaviours; reduced mean BMI and overweight prevalence. There was a 25.7% reduction in overweight prevalence post-intervention.
Bacopoulou et al., 2017 [93]	Mediterranean diet decreases adolescent waist circumference	Greece	Multicomponent-multilevel intervention	Explore the effects of a school-based educational intervention on nutritional habits and abdominal obesity indices	A 6-month school-based programme with 36 adolescent sessions, 9 parent sessions, and workshops for teachers and health staff, addressing the Mediterranean diet (MD), PA, and healthy body image. Tailored guidebooks and an educational website.	Dietary habits via KIDMED index, BMI, WC, waist-to-height ratio (WHtR), blood pressure. Measurements at baseline and post-intervention.	6 months	Increased adherence to the MD; reduced waist circumference, WHtR, overweight/obesity prevalence, and BP. Living with both parents and higher parental education were associated with better dietary adherence.
Shahnazi et al., 2016 [17]	Can the BASNEF Model Help to Develop Self-Administered Healthy Behavior in Iranian Youth?	Iran	Quasi-experimental intervention study	To determine the effectiveness of an educational intervention programme based on the BASNEF model to improve nutritional habits and lifestyle among high school students	Four educational sessions (120–150 min each), implementing dietary changes at school and home. Activities included hands-on tasks, video presentations, exhibitions, group discussions, and educational materials (pamphlets, CDs, and slides). Topics included obesity awareness, healthy eating habits, physical activity benefits, and dietary recommendations.	Beliefs and attitudes about nutrition using BASNEF scores. Frequency of physical activity. Evaluation through pretest, post-test, and follow-up with Likert-scale questionnaires and student diaries.	3 months (follow-up post-intervention)	Significant improvement in nutritional beliefs (79.2% for girls, 70.1% for boys) and attitudes (61.2% for girls, 59.4% for boys) in the intervention group compared to controls (p < 0.001). Physical activity increased significantly (p < 0.001). BASNEF model deemed effective for fostering long-term healthy habits.
Jamerson et al., 2016 [94]	Differences in Cardiovascular Disease Risk Factors and Health Behaviors between Black and Non-Black Students Participating in a School-Based Health Promotion Program	USA	Pre–post intervention, survey-based design	To compare cardiovascular disease (CVD) risk factors of black and non-black children participating in Project Healthy Schools (PHSs)	Project Healthy Schools Intervention: -A school-based wellness programme to reduce obesity and CVD risk by promoting healthy eating and physical activity. -Includes 10 interactive lessons, assemblies, school events, after-school activities, and collaboration with food service vendors for healthier meal options.	Primary outcome: -Changes in physiological measures (e.g., BMI, blood tests). Secondary outcome: -Changes in dietary habits, physical activity levels, and sedentary behaviour (self-reported surveys).	Baseline and follow-up measurements (time not specified)	At baseline, black students had higher rates of obesity and poorer health habits, while non-black students had worse lipid profiles. Post-intervention, both groups showed significant improvements in health behaviours and physiological measures. Early intervention is effective in modifying CVD risk, particularly in high-risk groups.
Lazorick et al., 2016 [95]	The MATCH Program: Long-Term Obesity Prevention Through a Middle School Based Intervention	USA	Quasi-experimental study	To evaluate the long-term effectiveness of MATCH, a school-based obesity intervention for adolescents, on BMI and health behaviours	MATCH integrated into regular 7th-grade curriculum. Teachers delivered 26–30 lessons in science and other classes over 14 weeks. Key components included: -Web-based BMI and nutrition tools; -Graphing software for personal data analysis; -Pedometers and non-food incentives.	BMI and zBMI (standardized BMI) changes. Weight categories (obesity incidence/remission). Self-reported dietary habits (e.g., sweetened beverage and snack intake, TV viewing time).	14 weeks (intervention) + 4 years (follow-up)	The MATCH group had a significant reduction in zBMI (−0.15 vs. +0.04 in control, p = 0.02). Lower obesity incidence (13% vs. 39%) and higher remission to healthy weight (40% vs. 26%) in the MATCH group. Improved health behaviours: reduced sweetened beverage/snack intake and TV viewing. MATCH demonstrates long-term potential for obesity prevention.
Souza et al., 2016 [96]	Promoting public health through nutrition labelling-a study in Brazil	Brazil	Quasi-experimental study	To evaluate the effectiveness of an educational intervention on nutrition labelling to promote healthy food choices	Participants received a 50 min dialogue and exposure session covering the following: -Nutrition-labelling legislation; -Importance of nutrition info for chronic disease prevention; -Traffic light system for sugar, fat, sodium, and fibre content; -Folder with educational material.	-Pretest and post-test questionnaire. -Questions assessed: • Frequency of consulting nutrition labels; • Ability to identify healthy foods using a traffic light system. -Statistical analysis: McNemar test and Wilcoxon test for response comparison (p < 0.05 significant).	30 days	Participants consulting nutrition labels increased significantly from 55.8% to 72.0% (p < 0.001). Borderline significance in changes regarding the purchase of packaged foods. The intervention was feasible, improved label usage knowledge, and reinforced the importance of healthy food choices.
Ishak et al., 2016 [97]	School-based intervention to prevent overweight and disordered eating in secondary school Malaysian adolescents: A study protocol	Malaysia	Quasi-experimental study	To promote a healthy lifestyle, prevent overweight, and reduce disordered eating among adolescents	-Target group: secondary school adolescents (ages 13–14). -Peer-education strategy: peers conveyed knowledge and taught skills. -Promoted the following: • Healthy eating habits; • Positive body image; • Active lifestyle.	-Parameters assessed at baseline, post-intervention, and 3-month follow-up: • Body weight; • Disordered eating; • Stages of change for diet and activity behaviours; • Body image, quality of life, self-esteem; • Knowledge, attitudes, and practices towards a healthy lifestyle; • Eating and physical activity behaviours.	Intervention duration not specified; assessments conducted over multiple time points	Results to be collected. Expected outcomes include positive effects on body weight and healthy lifestyle behaviours. Prevention of disordered eating and overweight. Improvements in quality of life, self-esteem, and peer educators’ health-related knowledge.
Heo et al., 2016 [98]	Behaviors and Knowledge of HealthCorps New York City High School Students: Nutrition, Mental Health, and Physical Activity	USA	Quasi-experimental	To evaluate effects of HealthCorps curricula on nutrition, mental health, and physical activity knowledge and behaviour	HealthCorps programme included classroom teaching, mentoring, wellness councils, afterschool clubs, health fairs, Teen Battle Chef, and Youth-Led Action Research.	Knowledge: nutrition, physical activity, and mental health; Behaviour: fruit/vegetable intake, breakfast consumption, SSB intake, energy-dense foods; changes by sex.	1 academic year (2012–2013)	Significant improvements in all knowledge domains (p < 0.05). Key behavioural changes: • Boys: increased fruit/vegetable intake (p = 0.03). • Girls: increased acceptance of fruits/vegetables, breakfast consumption, decreased consumption of sugary drinks (p < 0.05). -Knowledge–behaviour links stronger for boys.
Ogunsile and Ogundele, 2016 [99]	Effect of game-enhanced nutrition education on knowledge, attitude and practice of healthy eating among adolescents in Ibadan, Nigeria	Nigeria	Quasi-experimental (non-equivalent group)	To evaluate the main effect of nutrition education on knowledge, attitudes, and practices related to healthy eating among adolescents	Eight-week nutrition education programme conducted in Ibadan, Oyo State. Topics included nutritional needs, importance of breakfast, effects of sugary foods and drinks, etc. Sessions lasted 1 h 20 min weekly and were facilitated by a researcher and four trained assistants.	ANCOVA for knowledge, attitude, and practice of healthy eating; gender and geographical location effects analysed; post-test mean scores compared by group and location.	January–March 2014 3 months	Significant main effects of nutrition education on knowledge (36% variance), practice (31.3%), and attitude (12.1%). Moderate effect sizes for knowledge and practice. Urban participants had higher knowledge; peri-urban participants demonstrated better practices.
Gray, 2015 [100]	Linking implementation process to intervention outcomes in a middle school obesity prevention curriculum, ‘Choice, Control and Change’	USA	Cluster randomised Controlled trial	Assess the link between process evaluation components and outcomes of the “Choice, Control and Change” intervention	Curriculum aimed at improving energy balance-related behaviours (EBRBs) using social cognitive and self-determination theories. Included 24 lessons taught in science classes over 8–10 weeks. The intervention targeted increasing fruits/vegetables and water intake, reducing sweetened beverages, fast food, packaged snacks, and leisure screen time. Control schools received regular curriculum.	Process components evaluated using teacher observations, interviews, and student questionnaires. Outcomes measured via self-reported psychosocial and behavioural changes. Analysis included implementation categories and hierarchical linear models.	September–December 2006	High-implementation group showed significant behaviour and psychosocial improvements. Teacher implementation and student reception predicted sweetened beverage outcomes (p < 0.05). Student satisfaction correlated with behaviour and psychosocial outcomes (p < 0.05).
Healy et al., 2015 [101]	Impact of an intuitive eating education program on high school students’ eating attitudes	USA	Quasi-experimental study	To examine the effects of an intuitive eating (IE) education programme on eating attitudes among high school students	Instruction on IE principles using a PowerPoint presentation based on Intuitive Eating by Tribole and Resch. -Included 10 principles, such as 45 honouring hunger, rejecting the diet mentality, and coping with emotions without food. -Activities: hunger discovery scale, challenging the “food police,” and replacing negative self-talk with positive dialogue. -Delivered during health classes.	Changes in eating attitudes measured using the Intuitive Eating Scale and its subscales. -Sex differences analysed across conditions.	7 days	Significant gains in overall positive eating attitudes and “Unconditional Permission to Eat” subscale for the IE group; no effects of sex on outcomes.
Slawson et al., 2015 [102]	College students as facilitators in reducing adolescent obesity disparity in Southern Appalachia: Team Up for Healthy Living	USA	Cluster randomised trial	To develop and test a peer-based health education programme aimed at obesity prevention among high school students through improved peer norms around healthy eating and physical activity	Peer-led curriculum “Team Up for Healthy Living” with eight 40 min sessions delivered in high school Lifetime Wellness classes. Content: nutrition awareness, PA, leadership, communication skills. Peer facilitators: undergraduate students in public health, nutrition, kinesiology. Control group received standard curriculum.	Primary outcomes: BMI, dietary behaviours, PA, sedentary behaviours. Secondary outcomes: attitudes, self-efficacy, perceived behavioural control, social support, weight perception, unhealthy dieting, quality of life, and dental health. Outcomes assessed at baseline, 3, and 12 months post-baseline.	8-week intervention + 12-month follow-up	Expected reduction in BMI percentile and healthier behaviours.
Marchetti et al., 2015 [103]	Preventing Adolescents’ Diabesity: Design, Development, and First Evaluation of “gustavo in Gnam’s Planet”	Italy	Quasi-experimental design	To evaluate the impact of the “Gustavo” web game on improving knowledge of healthy diets and changing dietary behaviours among adolescents to prevent diabesity	-A web-based game (“Gustavo”) developed by a multidisciplinary team. Integrated behavioural theories: transtheoretical model, social cognitive theory, self-determination theory, elaboration likelihood model. Focus: knowledge enhancement, self-efficacy, self-regulation, and intrinsic motivation. Features included fun elements, feedback, rewards, and interactive storytelling.	Knowledge of healthy diets. Food frequency consumption (white meat, eggs, legumes, sugar snacks, fish). Participant engagement and usability of the game. Self-reported skills acquisition. Surveys and frequency comparisons before and after gameplay.	1 week	Increased knowledge of healthy diets. Significant dietary changes: increased consumption of white meat, eggs, legumes; reduced intake of sugary snacks. A total of 76.6% of participants found the game easy to use; 87.3% found the content clear. Further studies planned with a control group for long-term impact evaluation.
Sweat et al., 2015 [104]	Outcomes of The BODY Project: A Program to Halt Obesity and Its Medical Consequences in High School Students	USA	Quasi-experimental pretest—post-test	To evaluate the potential effectiveness of The BODY Project on preventing or delaying obesity-related diseases in adolescents from diverse, low-SES backgrounds in NYC public schools	Intervention provided by The BODY Project team. Free evaluations and services for participants. Medical evaluations conducted twice during the study. Emphasis on simplicity and cost-effectiveness.	Obesity-related disease prevention or delay. Potential for long-term behaviour improvements. Future focus on randomised-control design and integration of tools such as mobile phone apps to enhance effectiveness.	Cohort enrolled between 2007–2011 and followed for 1 year	Promising potential in delaying obesity-related diseases. Recommendations for randomised control trials and cost-effectiveness analysis for future research.
Lazorick et al., 2015 [105]	Improved Body Mass Index Measures Following a Middle School-Based Obesity Intervention-The MATCH Program	USA	Quasi-experimental design comparing intervention (MATCH) and control groups	To assess the effectiveness of the MATCH intervention on reducing BMI and promoting healthy behaviours in middle school students	MATCH curriculum delivered over 14 weeks in two schools by classroom teachers, integrated lessons into science and other classes, with tools such as notebooks for tracking progress and rewards (e.g., pedometers, water bottles).	Measured BMI, zBMI, BMI percentile, weight categories (CDC parameters), self-reported lifestyle behaviours via SEAT survey, fitness testing.	14 weeks of intervention; 1-year follow-up for MATCH schools only	Significant reduction in BMI measures in the MATCH group versus control; sustained zBMI improvements in overweight and obese subgroups after 1 year; no self-reported behavioural differences.

). This standardised approach ensures consistency across studies, reducing bias and enabling a systematic comparison of data.

3. Results

The initial database searches yielded 900 articles. Following this, all duplicates were removed (n = 212), as seen in the PRISMA flow diagram in Figure 1. The remaining articles (n = 688) were screened based on their titles and abstracts to see if they met the inclusion criteria and if they included key words or sentences in the title or abstract derived from the concepts in Table 1. The remaining articles (n = 150) were included for full data extraction. Following a secondary review, the included articles were further refined to exclude all studies conducted outside of the post-primary setting. Any articles which were heavily focused on physical activity (PA), i.e., making up approximately more than half of the intervention, were also excluded. The remaining articles (n = 50) were used to populate Table 2. Using quantitative content analysis, five key themes or categories were observed within these articles, and they were grouped accordingly.

3.1. Study Characteristics

This scoping review highlights the extent to which interventions targeting adolescent dietary behaviours are being implemented globally, with studies spanning six continents, as shown in Figure 2. The largest proportion of research was conducted in North America (n = 18), likely reflecting the region’s strong focus on addressing DRDs, given the fact that NCDs are the leading cause of mortality in North America [106]. However, this geographic concentration may limit the generalisability of the findings to other educational systems, particularly those in low- and middle-income countries, where curricular structures, health priorities, and resource availability may differ significantly. The remaining studies were carried out in Asia (n = 15), Europe (n = 9), South America (n = 3), Oceania (n = 3), and Africa (n = 2).

The duration of the included studies exhibited considerable variability, reflecting the diverse methodological approaches employed to evaluate each intervention, respectively. Intervention lengths ranged from as brief as 1 h to as extensive as 4 years, allowing for the assessment of both short and long-term outcomes. More than half of studies (n = 29) fell within a duration of 3 months to 1 year, striking a balance between practical implementation and the opportunity to observe meaningful behavioural changes. Notably, three studies did not specify a duration [79,94,97], while one study evaluated a previously completed intervention; therefore, the study duration was inconsequential [91].

3.2. Knowledge and/or Behaviour-Focused Interventions

Interventions which had a focus on knowledge and behavioural changes formed a significant portion of the reviewed literature, with studies frequently employing structured nutrition and health education sessions aimed at fostering healthier eating habits among adolescents (n = 15). These interventions frequently relied on established behavioural theories, including the social cognitive theory, transtheoretical model, and health belief model, to guide programme development and implementation [58,76,85,86,88,100]. Theoretical underpinnings enabled a focus on elements such as knowledge acquisition, self-efficacy, goal setting, and behaviour modification. Sessions were typically classroom-based and tailored to the age group, aiming to make nutrition concepts accessible and relevant to students [70,84]. A key advantage of education-based interventions is their ability to be incorporated into existing school curricula, making them logistically feasible and cost-effective [76]. The content covered ranged from basic nutritional knowledge such as understanding macronutrients and portion sizes to practical applications, such as meal planning and label reading [17,74,96,101]. The duration of these interventions varied from a few weeks to several months, with more extended programs often showing greater impact [63,70,72,74] with the exception of one study (Westfall et al., 2020 [74]).

However, challenges were noted, including varying levels of student engagement and retention of information. Some studies highlighted the importance of interactive and participatory elements, such as discussions, group activities, and hands-on demonstrations, to enhance the learning experience [17,70]. Additionally, studies emphasised the need for culturally appropriate content to address the diverse dietary habits and preferences of adolescents around the world [17,63].

3.3. Interventions Focused on Diet-Related Diseases

A number of studies (n = 14) employed interventions aimed at preventing or managing DRDs, such as obesity, type 2 diabetes, and cardiovascular conditions. These programmes emphasised the link between dietary behaviours and health outcomes, often incorporating specific dietary recommendations tailored to the disease in focus [89]. DRD-targeting interventions generally adopted a two-pronged approach: providing foundational knowledge about the disease and equipping participants with actionable strategies to manage or mitigate risk [69,75,89,100]. Several interventions also integrated components on physical activity and stress management, recognising the multifaceted nature of DRDs [75,78,90]. The educational delivery methods varied, with some relying on traditional didactic approaches, while others used multimedia resources, visual aids, and interactive workshops to engage participants.

Challenges associated with DRD-focused education, including the potential for stigmatisation, particularly among overweight or obese adolescents, were discussed by Fernandez-Jimenez et al. [78]. Researchers, including Schapiro et al. [66] and Selamat [69], emphasised the importance of a non-judgmental and supportive approach to foster inclusivity and engagement. Another critical factor noted by Schapiro et al. [66] and Fernandez-Jimenez et al. [78] was the involvement of families, as dietary habits are often shaped within the household context. Programmes that included some level of parent workshops or take-home materials reported improved outcomes, suggesting that extending education beyond the classroom enhances effectiveness [93].

3.4. Interventions Involving Gamified/Digital or Interactive Learning

The use of gamified or interactive learning tools to educate adolescents about healthy eating was another key theme explored within some articles (n = 6). These interventions employed innovative methods, such as educational games [60], digital simulations [103], and interactive booklets [77], to increase engagement and improve learning outcomes. The gamified approach capitalised on adolescents’ preference for interactive and technology-based activities, making it particularly appealing for the post-primary cohort [60,103]. Some games and simulations incorporated scenarios requiring participants to make dietary decisions, providing immediate feedback on their choices [60,103]. For instance, some programs used computer-based tools that allowed students to simulate meal planning or navigate virtual grocery stores, reinforcing concepts such as balanced diets and budget-friendly shopping [60]. Other interventions involved more hands-on activities, such as interactive food challenges or organising a cooking show [59], which encouraged skill-building alongside knowledge acquisition. The use of rewards and challenges within these tools helped sustain motivation and participation, while the interactive nature facilitated active learning [103]. Shen et al. [73] discussed the use of a smartphone app which tracked students’ self-reported biometrics and issued tailored feedback to them. Studies frequently highlighted the role of enjoyment and fun in enhancing the effectiveness of these programs, as adolescents were more likely to remain engaged and internalise lessons when the learning process was entertaining [59,103]. The limitations of gamified approaches included the potential for unequal access to technology and the risk of oversimplifying complex nutritional concepts [99]. Additionally, the novelty of the approach often posed challenges in aligning the games’ content with standardised curricula.

3.5. Involvement of External or Peer Facilitators

The use of some form of external facilitation to promote healthier eating behaviours among adolescents was observed in multiple studies (n = 7). Partida et al. [87] and Slawson et al. [102] noted the role of healthcare professionals, such as dietitians or university students, in delivering these interventions, adding a layer of credibility and expertise. Saez et al. [82] researched peer-led interventions, which often involved older students or trained adolescent leaders conducting workshops, cooking demonstrations, or discussion groups. The relatable nature of peer educators was found to enhance engagement and credibility, as participants were more likely to trust and emulate individuals close to their age [97,98]. This type of intervention emphasised the social and cultural dimensions of eating, with activities designed to reflect the dietary practices and preferences of the target population. Challenges in implementing these interventions were identified by Saez et al. [82] and included logistical issues, such as training peer educators and coordinating with community stakeholders. Additionally, as Heo et al. [98] outlined, maintaining consistency and quality across diverse settings posed significant hurdles. Nonetheless, the social aspects of these programs, as noted by Huitink et al. [68], often led to improved attitudes towards healthy eating and increased confidence in making healthier food choices.

3.6. Adjustments to the School Food Environment

A number of studies utilised adjustments to the school’s food environment (n = 8) in order to improve dietary behaviours among students. These interventions involved structural [65] and policy [67] modifications within schools to create environments that facilitated healthier food choices. Common strategies included the introduction of healthy vending machines [71], the installation of water stations [65], and adjustments to cafeteria offerings, such as featuring prominently displayed fruits and vegetables or reducing the availability of sugary snacks [79]. Some programmes also incorporated promotional campaigns, using posters, announcements, or student ambassadors to increase awareness and encourage participation [91,94]. The rationale for these interventions lies in the substantial amount of time adolescents spend in school, making it a critical setting for influencing dietary behaviours. By modifying the “choice architecture” of the school food environment, these interventions aimed to make healthier options more accessible and appealing [79]. Studies emphasised the importance of visibility and convenience, noting that small changes, such as placing water bottles at eye level, significantly influenced students’ selections [79]. As outlined by Askelson et al. [81], barriers to implementation included resistance from stakeholders, such as cafeteria staff or school administrators, particularly when interventions impacted revenue from less healthy but popular options. Additionally, interventions were often limited by budget constraints and there was a need for external funding [67]. Despite these challenges, school-environment changes were effective in shifting consumption patterns, particularly when combined with educational components [65,71,81].

4. Discussion

This paper aimed to map the literature relevant to school-based food and NE programmes aimed at adolescents and in particular, those programmes focused on altering dietary behaviours in this demographic.

4.1. Knowledge- and/or Behaviour-Focused Interventions

Numerous interventions (n = 15) focused on improving general knowledge, attitudes, and behaviours relating to healthy eating, without targeting a specific DRD. Instead, they prioritised providing the participating students with a strong food literacy foundation, along with the skills needed to make educated choices regarding their diet. They often taught participants important knowledge about macronutrients, portion sizes, and the advantages of a balanced diet, all of which are pertinent to creating a healthy lifestyle. In addition to this, many interventions incorporated practical components, such as cooking demonstrations, meal planning exercises, and food label reading activities, to help participants apply their knowledge to real-world scenarios. Embedding these programs into school curricula ensured accessibility and allowed for consistent delivery, while tailoring content to the developmental stage of participants made lessons more engaging and relevant. Despite these strengths, some studies highlighted challenges, including varying levels of student engagement and retention, as well as the need for culturally tailored materials to address diverse dietary habits and preferences. While foundational knowledge is essential, it may not translate into meaningful behavioural change without deeper structural or socio-environmental support [107]. Additionally, the general focus on health education limited the ability to measure direct impacts on specific DRDs, limiting its applicability for high-risk populations. While these broad interventions lay the groundwork for healthier populations, combining them with targeted programs for specific conditions could maximise their impact. However, it is important to note that such programmes, particularly those embedded into curricula with hands-on components such as cooking or label-reading, may incur significant staffing, training, and material costs. Future planning should consider scalable models and cost–benefit analyses to support broader implementation in resource-limited schools.

4.2. Interventions Focused on Diet-Related Diseases

When left unmanaged, DRDs, such as obesity and diabetes, significantly shorten life expectancy [61]. DRDs demand long-term care, straining healthcare budgets and diverting resources from areas such as infectious diseases, maternal health, and prevention. A number of studies (n = 14) offered valuable information about the effectiveness of interventions aimed at DRDs, with the majority placing a critical focus on obesity (n = 10). One justification for this priority may be due to the high prevalence of overweight and obesity within the post-primary cohort of children globally. Furthermore, more than half of these studies relating to obesity (n = 6) were conducted in the USA, which could indicate an attempt to curb their increasingly high rates of obesity in both the adolescent and adult population [66,80,95,98,104,105]. All studies (n = 11) reported being successful to some extent in achieving their desired targets and goals. Many studies utilised anthropometric measurements such as BMI, waist circumference, and waist-to-hip ratio to track quantifiable data over the course of the interventions (n = 7). The use of clear and standardised anthropometric measures positively contributes to evidence-based decision making when analysing the effectiveness of the intervention. However, as stated, a large portion of these studies were conducted in the USA, which may hinder the generalisability of such interventions on a large scale, as contexts may vary across populations. For instance, interventions development in high-income contexts may not account for cultural, socioeconomic, or structural barriers in lower-resource settings. Furthermore, there is potential that publication bias may have led to the absence of similar studies that were unsuccessful or did not receive desired results. Although clinical outcomes such as BMI or waist circumference provide compelling evidence, these assessments require trained personnel and equipment, which can increase implementation costs. Evaluating the cost-effectiveness of such interventions will be essential to guide sustainable investment by health and education sectors.

4.3. Interventions Involving Gamified/Digital or Interactive Learning

The use of gamified or interactive learning interventions is a novel pedagogical approach to improving dietary behaviours among adolescents. Within this review, studies offered a combination of positive outcomes, as well as notable limitations. Numerous studies demonstrated improvements in knowledge comprehension, such as enhanced quiz performance [77] and increased awareness of nutrition and food systems [60,99], which could suggest that this is an effective method of engaging students in learning complex concepts. However, the limited impact on behavioural change in some studies, such as the inability of one intervention to significantly shift parental perceptions of students’ nutritional status [73] or to promote healthier behaviours despite being engaging [59], underscores the gap between knowledge gains and sustained practical outcomes. The novelty of the gaming experience could be enough to boost short-term extrinsic motivation, yet it may fail to impart lasting internalised behaviour. The impact of the studies varied considerably, largely due to the differences in study designs. For example, one study found significant dietary changes, including higher intake of white meat, eggs, and legumes, along with a reduction in sugary snacks [103]. In contrast, other studies concentrated mainly on short-term improvements in knowledge and understanding, with limited evidence supporting sustained behavioural change [99]. This suggests that engagement alone may be insufficient for sustained behavioural change without complementary strategies such as the intervention design, the target demographic, and cultural relevance. Despite encouraging short-term gains in knowledge and dietary habits, the lack of extended follow-up in many studies limits the opportunity to assess the long-term sustainability and real-world impact of gamified interventions. Moreover, while digital tools and games can increase engagement, development and technology access costs may present barriers to equity and scalability, particularly in under-resourced regions. Future studies should explore the balance between initial investment and long-term educational return.

4.4. Involvement of External or Peer Facilitators

By using peers of an interventions’ target population, some studies were able to successfully increase engagement and participation levels among students [82,97,98]. Through fostering relatability and more approachable social support, students develop deeper understanding and are more motivated to adopt healthier eating behaviours. In order to improve their general relatability and approachability, two studies emphasised the use of peer facilitators who are chosen based on their strong leadership qualities or their comparable socioeconomic position to the students participating in the intervention [82]. However, peer relatability is not guaranteed; therefore, it is crucial to take cultural and social variables into account when choosing peer leaders to make sure they can, to the best of their ability, inspire and connect with the learners involved. However, youth peers do invite the possibility of spreading misinformation if improperly informed, as well as the risk of peer pressure or a power dynamic in some settings.

Other studies benefited from the inclusion of external facilitators, such as college students, dietitians, or nutritionists, to help provide guidance and specialised knowledge to peer facilitators through lessons on nutrition, physical activity, and self-efficacy. The expertise that they provide can further contribute to the effectiveness of an intervention by improving the participants’ knowledge in specific areas, such as the relationship between protein intake and exercise [68,87,102]. Although external facilitators offer experience, their recruitment is resource-intensive, which might restrict intervention scalability, particularly in underfunded education settings. In order to ensure that specialised knowledge is presented in an approachable and interesting way, the most successful interventions integrate the advantages of peer-led elements and external facilitators. However, some of the major limitations of these studies included their reliance on self-reported data in the form of post-study surveys, which may introduce bias. Another limitation would be the concept that the effectiveness of peer-led initiatives is directly linked to the learner’s individual situation, which can vary across different contexts and demographics. Customisability seems necessary to address socio-cultural variation; however, this introduces further challenges, such as the standardisation of interventions. Additionally, the reliance on either peer or external facilitators can significantly affect intervention costs and feasibility. While peer-led approaches may offer a low-cost alternative, they require robust training frameworks. In contrast, external facilitators enhance quality but increase programme costs. Careful consideration of these trade-offs is necessary when designing scalable models.

4.5. Adjustments to the School Food Environment

A number of studies (n = 8) facilitated interventions that mainly focused on or had elements involving adjustments to the school’s food environment. Despite varied approaches, all of these aimed to reshape the school food environment to encourage healthier behaviours, yet the consistency and depth of implementation varied greatly. Rearranging food placement to make healthier options easier to choose showed potential, but its impact was limited by mixed messages and a lack of readily available healthy choices [79]. The cause of this shortfall is unclear, but it could be due to budget, supply chain issues, or school policies which limited the healthy food options made available. Furthermore, some students found it difficult to prioritise the available healthy foods when there were still unhealthy options to choose from [79]. Other studies took a more compressive approach and included adjustments to the schools’ food environment, such as healthier canteen menu options, alongside educational learning opportunities [91,92,94]. The results of the initiatives indicated improvements in health metrics such as cholesterol, blood pressure, and obesity levels among participants, along with notable increases in healthy eating behaviours and nutritional understanding [91,92]. Another study took an approach that focused on improving the canteen atmosphere and fostering better interactions with staff, alongside increasing the availability of dairy, vegetables, and fruits [81]. This consequently lead the majority of participating schools to achieve their goals of increased healthy food consumption. An intervention targeting sugar-sweetened beverage consumption in disadvantaged Australian schools [67] achieved only modest reductions, underscoring the difficulty of driving behavioural change in such contexts. In contrast, the “Thirsty? Choose Water!” campaign effectively reduced sugary drink intake and boosted water consumption and the use of reusable water bottles, through the provision of chilled water stations and targeted education [65]. One explanation for the effectiveness of these two beverage-focused studies, could be the duration, with the more successful one taking place over the course of one year, compared to 6 months. Collectively, these findings highlight the potential of school-based interventions while emphasising the need for well-funded, multifaceted strategies and extended durations to ensure lasting impact and sustained behavioural change. However, environmental changes, such as menu modifications or infrastructure improvements (e.g., chilled water stations) can carry substantial upfront and maintenance costs. Without adequate budgeting and long-term funding models, such changes may not be sustainable. Policymakers should prioritise interventions with demonstrated cost-effectiveness and feasibility in varying economic contexts.

4.6. Limitations and Future Directions

A predominant issue across many studies was the absence of long-term follow-up, limiting understanding of whether observed behavioural changes were sustained after the intervention period concluded. Furthermore, a heavy reliance on self-reported data, particularly in peer-led and gamified interventions, raises concerns around accuracy due to recall bias and social desirability, possibly leading to an exaggeration of effectiveness. Future research should consider integrating objective measures where possible, such as wearable devices or teacher-reported behavioural logs, to triangulate data and improve validity. Interventions involving clinical metrics (e.g., cholesterol or BMI) faced additional challenges, as ethical approval and clinical oversight are difficult to secure in school settings unless qualified health professionals are included as part of the intervention team. This raises questions around feasibility and role clarity, especially in under-resourced schools, where there may be tension or confusion around health-related responsibilities. To address this, partnerships with community health services or mobile clinics could offer a viable alternative for data collection and oversight without overburdening school staff. Moreover, many interventions were implemented in specific cultural or socioeconomic contexts, most notably in high-income settings such as the U.S., which limits generalisability to other regions. Although the studies spanned diverse cultural contexts, few reported how interventions were meaningfully adapted to fit local norms and practices. Where cultural tailoring was mentioned, it was often limited to translation or familiar food examples. This highlights a need for more intentional and transparent cultural adaptation in future nutrition education research. Adaptable intervention models and inclusive study designs that involve co-creation with local stakeholders can help enhance cultural relevance and scalability across diverse settings. Future studies should focus on flexible, practical approaches that take into account different school settings and real-world challenges, while also being mindful of ethics and available resources. It is acknowledged that long-term research in school settings is often limited by ethical considerations, the complexity of controlling for confounding variables, time constraints, and potential crossover between educational and clinical responsibilities. Further research should also explore the long-term impacts of nutrition education, including potential effects on body weight and cardio-metabolic outcomes, particularly during key developmental stages such as pre-puberty. Equally important is the integration of economic evaluations in future research to assess cost-effectiveness and inform policy-level decision-making. Clear reporting of resource use, staffing requirements, and delivery costs will support the development of scalable and sustainable programmes.

5. Conclusions

This scoping review aimed to map the current literature relating to the efficacy of post-primary NE interventions and their potential to halt the rising concern of DRDs. The findings partially support this aim; however, the strength of the conclusions must be interpreted with caution due to the heterogeneity of study designs, intervention components, and outcome measures, as well as several methodological limitations present across the included studies. While many interventions led to improvements in nutritional knowledge and short-term behaviour, fewer demonstrated sustained change or consistent clinical outcomes. This suggests that the success of such programmes depends heavily on factors such as intervention design, duration, cultural relevance, and available resources. Accordingly, broader generalisations about intervention effectiveness should be avoided without further high-quality evidence. Future work would benefit from the inclusion of longitudinal studies alongside culturally tailored interventions to evaluate the impact overtime across diverse school settings. In light of these findings, it is recommended that policymakers prioritise sustained, theory-based NE interventions that are contextually adaptable and supported by adequate resources. Schools should integrate NE more holistically into the curriculum, ensuring the programmes are age-appropriate, culturally relevant, and designed with input from educators, health professionals, and families. Intervention designers are encouraged to align future programmes with behavioural change theories and include mechanisms for long-term follow-up to assess lasting impact.