School-based interventions targeting double burden of malnutrition and educational outcomes of adolescents in low- and middle-income countries: protocol for a systematic review

Background Adolescence is a period of rapid physical growth and transition between childhood to adulthood. However, in many developing countries, nutritional and epidemiological transitions are contributing to surging overnutrition, which, together with prevalent undernutrition, is resulting in the double burden of malnutrition (DBM) among adolescents. Schools as social systems have tremendous but mostly underutilized capacity to facilitate change and address a range of nutritional and associated educational concerns of adolescents and young people. The main objective of this systematic review will be to describe school-based interventions that address the multiple forms of malnutrition, and synthesize their effects on nutrition and educational outcomes among adolescents (10 − 19 − years − old) from low- and middle-income countries (LMICs). Methods Comprehensive literature searches will be conducted in multiple electronic databases, including Medline (through PubMed), Embase, CENTRAL (through Cochrane Library), CINAHL, and Google Scholar. We will include randomized controlled trials (RCTs), non-RCTs including controlled before-after studies, examining the effects of nutrition interventions on nutrition and educational outcomes among adolescents in LMICs. Two reviewers will independently screen all citations and full-text articles and abstract data. The quality of the included studies will be assessed with the Cochrane Collaboration’s revised tool for assessing the risk of bias for RCTs and the Risk Of Bias In Non-randomized Studies of Interventions tool for controlled before-after studies and non-randomized controlled trials. Discussion To maximize the power of schools as a platform to reinforce the mutually beneficial relationship between adolescent nutrition and education, it is imperative to develop and implement integrated interventions connecting schools, adolescents, parents, communities, and the health care system. The results of this systematic review may provide a comprehensive state of current knowledge on the effectiveness of school-based interventions to enable future research that maximizes the impact and efficiency of integrated approaches to tackle multiple forms of malnutrition among school-going and out-of-school adolescents. Systematic review registration PROSPERO ID: CRD42020211109 Supplementary Information The online version contains supplementary material available at 10.1186/s13643-021-01756-9.


Background
Low-and middle-income countries (LMICs) formerly that suffer from a high prevalence of undernutrition (i.e., underweight, stunting, thinness, or wasting) are now facing the additional burden of overnutrition (i.e. Loading [MathJax]/jax/output/CommonHTML/jax.js overweight or obesity).This is referred to as the "double burden of malnutrition" (DBM).Originally identi ed in adults, the DBM is now affecting children, and adolescents across LMICs [1].Approximately 1.2 billion adolescents aged 10 − 19 years today make up 16% of the world's population, of which 90% live in LMICs [2].The Global School-based Student Health and Health Behaviour Survey between 2003 and 2013, in 129, 276 school-aged adolescents (aged 12 − 15 years) from 57 LMICs estimated the prevalence of stunting as 10.2%, the prevalence of thinness as 5.5%, the prevalence of overweight or obesity as 21.4% and the prevalence of concurrent stunting and overweight or obesity as 2.0% [3].Thus, DBM in adolescents in LMICs is considered to be a signi cant public health concern.The consequences of concurrent undernutrition and overnutrition in adolescents and later in adulthood are associated with poor muscle strength, reduced bone density, delayed onset of puberty, poor cognitive development and academic performance, early onset of adult chronic diseases (type 2 diabetes, hypertension), poor work capacity and reproductive outcomes in adulthood, particularly for females because of the heightened obstetric risks [4].In this perspective, changes in diet and health behaviors are likely to have major effects on the individual's current and future health [5,6].
Education is one of the most powerful determinants of adolescent health and a driver of economic progress to a successful transition to adulthood.Given the bidirectional relationship between health and nutrition on the one hand, and educational outcomes on the other [5], schools offer a promising platform for addressing nutritional issues of adolescents.Furthermore, schools and peers have a central role in adolescents' social lives, thus in uencing multiple health behaviors, diet habits, and educational outcomes [7].This is particularly the case given the global expansion of school attendance [8].Because schools are at the heart of all communities, there is an opportunity to use the school as a sustainable, scalable option to reinforce health messages and address malnutrition for both school-going and out-ofschool adolescents.
Several systematic reviews suggest promising but modest evidence of bene t from addressing the single form of malnutrition through discrete school − based nutrition interventions (e.g., nutrition education, physical activity, and micronutrients through forti cation and targeted supplementation, school feeding, school gardens, and access to a safe environment and hygiene) [9 − 19].These food supplementations and/or forti cation interventions are effective in reducing micronutrient de ciencies and can improve nutrition status [9,17].Evidence on school-based nutrition education interventions suggests that these interventions can improve nutrition knowledge, but this may not necessarily translate into healthy nutrition behavior, indicating that nutrition knowledge may have little impact without a facilitating environment [15,19].Also, single-domain adolescent nutrition interventions target either undernutrition or overnutrition and function in silos.Hence, there is increasing interest in schools addressing health and nutrition behaviors through multi-component integrated interventions, generally called "double-duty actions" [4], to target all forms of malnutrition and non-communicable diseases.The linchpin of this proposition is the no harm notion that addressing one form of malnutrition should not be detrimental to subsequently tackling another form of malnutrition.Evidence on integrated interventions is promising in Loading [MathJax]/jax/output/CommonHTML/jax.js improving the nutritional status of school-going children and adolescents.However, it comes largely from high-income countries and hence has limited generalizability [20][21][22][23][24][25][26][27].
Given the limited systematic reviews of evidence particularly from LMICs, we aim to conduct a comprehensive review of the published literature to characterize school-based nutrition interventions that focused on addressing multiple forms of malnutrition and educational outcomes of adolescents (aged 10 to 19 years) in LMICs.We will emphasize ndings generated from effectiveness studies of nutrition interventions such as focusing on individuals as well as school environment and policies to improve the nutritional status and educational outcomes of adolescents with the involvement of parents and wider communities, and provision of school-based health services.We will include ndings generated from randomized controlled trials (RCTs) and other rigorously designed interventional studies, including controlled before-after studies (CBAs) and non-randomized controlled trials that accounted for the baseline differences between intervention arms.

Conceptual framework
The newly developed agenda for Sustainable Development 2030 has recognized a need for greater accountability especially for the Global Strategy for Women's, Children's and Adolescents' Health [28].It has called for increased participatory frameworks across a range of areas relevant to young people including non-communicable disease risks and nutrition.We developed a conceptual framework based on existing conceptual frameworks and the recommendations [29,30].We identi ed a set of interventions to be incorporated in our review process.These interventions are chosen from the existing work based on proven and potential effectiveness to address malnutrition in adolescents (aged 10-19 years).
Well-nourished adolescents protected from disease, infection, and early pregnancy are less likely to develop malnutrition in all its forms during adolescence and adulthood and are more likely to avoid noncommunicable diseases, have optimal maternal and birth outcomes, and enjoy increased work capacity and productivity.Various individual and general risk factors throughout the life cycle including adolescence can have implications for the nutritional status of adolescents.These risk factors are not independent of each other and impact the adolescence stage, the next stage of life as well as can also have intergenerational effects.We will not divulge further into this as the purpose of this study is to review the potential interventions which could address the multiple forms of malnutrition in adolescents.1.We will include randomized controlled trials, with the intervention randomized to individuals or in clusters (including classes, schools, and groups/clubs).We will also include controlled before-after studies as they are non-randomized studies with a relatively rigorous design and occupy a nonnegligible proportion of the relevant literature.Non-randomized controlled trials will also be eligible for inclusion as long as the baseline differences between study arms are accounted for in the analysis.
2. Studies involving adolescents (boys and girls) aged 10 to 19 years.
3. Studies conducted in LMICs-as de ned by the World Bank in the year 2020 [31].

Studies addressing the following outcomes:
For DBM: Change in nutritional status measured by anthropometry (e.g., physical activity, height-forage z scores, weight-for-age z scores, weight-for-height z scores, skin-fold thickness measures, stunting, underweight, wasting, body mass index, overweight, obesity, waist-to-height ratio, and central obesity), and knowledge of and practices related to diet.
For educational di culties: school enrolment, school completion, school attendance, prevention of school absenteeism and/or drop-out, and cognitive, maths, and/or language skills .The control (comparison) in each included study can be participants who did not receive any intervention or received general health education intervention.
7. We will include published articles and ongoing studies for which preliminary ndings are available.
. We will not place any restrictions in terms of the year of publication, language, sample size of the study, or duration of the intervention provided.

Exclusion criteria
We will not consider the following studies: 1. Non-randomized controlled trials that did not account for the baseline differences between the study arms; 2. Studies without a proper control (comparison) group/arm; e.g., uncontrolled before-after studies,

Information sources
The following principal sources of electronic reference libraries will be searched: Medline (through PubMed), Embase, CENTRAL (through the Cochrane Library), CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Google Scholar.All databases will be searched for eligible studies from the inception of each database through September 2020.Detailed examination of cross-references and bibliographies of available publications to identify additional sources of information will also be performed.This search of studies will be supplemented by reviewing organizational websites such as the World Food Programme, World Bank, Food and Agriculture Organization, United Nations Children's Fund, and United Nations Population Fund.Articles written in languages other than English will be translated by colleagues who are native speakers, whenever possible.Studies that cannot be adequately translated will be excluded.

Search strategy
Guided by the conceptual framework, a broad search strategy (e.g.type of study [randomized controlled trial OR controlled before-after studies OR quasi-experimental studies] AND intervention domain [nutrition] AND population [adolescents] AND setting [low-and middle-income countries]) will be performed in PubMed without time restrictions.We consulted with a health science librarian to develop the PubMed search strategy, which is provided in Additional File 1.The sensitivity of the search strategy will be examined by con rming that several sentinel articles are identi ed.The PubMed strategy will be adapted to the syntax appropriate for other databases.The following details will be documented for each search: databases searched, date of search conducted on, search strategy (i.e., subject headings and keywords Loading [MathJax]/jax/output/CommonHTML/jax.js used, including whether terms are exploded, truncated and how terms are combined), years searched, lters used, number of results retrieved for each search, the total number of records, duplicates identi ed, and numbers pre-and post-screening.Also, all publications identi ed through hand searching will be noted with a source (i.e., name of journal/website, conference proceedings, etc.) and the years.

Data Management
EndNote X9 (Clarivate Analytics, PA, USA) will be used to store the records retrieved from searches of electronic databases.The records will also be imported into Covidence (Veritas Health Innovation, Melbourne, Australia), an internet-based program that facilitates the streamlined management of the systematic review.Duplicate records will be detected and removed rst by EndNote and then by Covidence.
Two reviewers will independently assess the search results based on the inclusion and exclusion criteria.First, all searched titles and abstracts will be reviewed to exclude irrelevant studies.Disagreements between the two reviewers will be resolved by discussion or by a third reviewer, if necessary.
The interrater agreement will be quanti ed by calculating the raw percentage of agreement and Cohen's κ coe cient.A study ow diagram will be maintained as recommended by the PRISMA statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) [32], with the speci c reasons for excluding studies.Neither of the reviewers will be blind to journal titles or the names of the authors.

Data extraction
Two reviewers will independently extract and enter the data of studies included in the review.A data extraction form provided as Additional File 2, will be developed and then pilot-tested on ve randomly selected studies.The following information will be extracted for each selected study: title, authors ( rst author and corresponding author), contact information of corresponding author, journal (or source for reports), year of publication, year of intervention implementation, country and geographical setting, study design, sample size (if a cluster randomised trial, number of clusters and average cluster size), sample characteristics (e.g., age, sex, and socioeconomic status of the participants), intervention (including duration, intervention type, guiding theory/framework, intervention description, delivery mechanisms and agents, and procedures employed for selection, training and supervision of delivery agents, intervention coverage and delity information, and challenges and barriers encountered in intervention delivery), measure of adherence, information on control/comparison intervention, outcomes assessed, time-points, main ndings with point estimates and measures of variance (standard errors, 95% CI and/or p-values), and reasons provided for success/failure.Multiple reports of a single study will be collated as additional results may be provided in different reports.In case of missing information or inconsistent results across reports of a single study, we will contact the corresponding author via email to obtain more accurate results or additional information.A maximum of two contact attempts will be made.

Quality assessment
For the assessment of the risk of bias of the selected studies, we will use the Cochrane Collaboration's tool for assessing the risk of bias in randomized trials [33,34].Two reviewers will independently evaluate methodological quality.Any uncertainties or disagreements will be resolved by discussion or by a third reviewer, whenever needed.The tool is a domain-based evaluation, in which critical assessments will be made separately for the bias arising from the randomization process, the bias due to deviation from intended interventions, the bias due to missing outcome data, the bias in the measurement of the outcome, and selective outcome reporting.The judgment for each entry will involve assessing the risk of bias as "low risk," as "high risk," or as "some concerns," with the last category indicating either lack of information or uncertainty about the potential for bias.
We will use the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool [35], to assess the risk of bias for controlled before-after studies and non-randomized controlled trials.This tool considers biases from confounding, the bias in selection of participants into the study, the bias in classi cation of interventions, bias due to deviations from intended interventions, the bias due to missing data, the bias in the measurement of outcomes, and the bias in selection of the reported results.Each domain will be judged as "low risk of bias," "moderate risk of bias," "serious risk of bias," "critical risk of bias," or "no information."Based on the domain-speci c judgments, we will consider a non-randomized study (a) at low risk of bias if it is judged to have a low or moderate risk of bias for all domains; or (b) at high risk of bias if it is judged to have a serious or critical risk of bias in one or more domains; or (c) have some concerns if the assessment is unclear for one or more domains but low or moderate for all other domains.We will contact the corresponding authors of the reports to obtain more information, when necessary.We will summarize the results of the assessment of the risk of bias in a table, in which the judgment for each domain will be presented with a justi cation.

Synthesis of evidence
A systematic and narrative synthesis of all included studies will be presented in the text as well as in a table.Based on our conceptual framework, the interventions will be identi ed by an iterative process of data collating and key ndings will be broken down into speci c categories, derived from the articles.We will not conduct the meta-analyses given the considerable heterogeneity of both the interventions and outcomes.
We will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and guidelines to ensure a robust and replicable process [36].Effect estimates for continuous outcomes will be expressed as mean differences (with 95% CI) comparing the intervention group with the control group; effect estimates for dichotomous outcomes will be expressed as risk ratios, rate ratios, hazard ratios, or odds ratios (all with 95% CI), comparing the intervention group with the control group.

Registration and reporting
This protocol is submitted for registration with the International Prospective Register of Systematic Reviews (PROSPERO) on September, 24 2020 (ID 211109).In the event of protocol amendments, the date of each amendment will be accompanied by a description of each change and the rationale on PROSPERO.
This protocol is written following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) [36].The PRISMA-P checklist can be obtained from Additional File 3. We will report this systematic review following the Cochrane Handbook for Systematic Reviews of Interventions [37] and the PRISMA guidelines [32,36].

Discussion
Combating malnutrition in all its forms is one of the greatest global health challenges in uenced by economic and income growth, urbanization and globalization, and related shifts in the quality and quantity of human diets.In 2016, the United Nations Decade of Action on Nutrition for the period 2016 − 2025 came to life [38], which calls for speci c coordinated actions through cross-cutting and coherent policies, programs, and initiatives to address increasing DBM.As the global community transitions from a predominant focus on the eradication of severe and acute undernutrition within the framework of the Millennium Development Goals to the broader nutrition focus of the Sustainable Development Goals, including all forms of malnutrition and noncommunicable diseases, addressing DBM offers an unexplored window of opportunity for integrated actions.The agenda for Sustainable Development 2030 has also identi ed a need for tracking indicators to meet targets, especially for the Global Strategy for Women's, Children's and Adolescents' Health [28].The major causes of deaths, disabilities, illnesses, and social problems among adolescents and young people are established during childhood and adolescence.In this review, we will focus on DBM in adolescents for multiple reasons.First, adolescence is a critical period for growth and development, with higher nutritional demands placing adolescents at greater risks of malnutrition.Malnutrition during adolescence manifests in three broad groups of conditions: undernutrition (wasting, stunting or chronic undernutrition and thinness or underweight): micronutrient de ciency or excess (inadequate or excessive intake of vitamins or minerals); and overweight and obesity.Among adolescents, undernutrition and micronutrient de ciencies are associated with poor physical growth, impaired cognitive and motor development, delayed maturation, impaired school achievement, reduced economic productivity, and poor reproductive health outcomes in females [39,40].Obesity and overweight in adolescence have been associated with an increased risk of early onset of adult chronic diseases such as type 2 diabetes, heart disease, stroke, hypertension, some cancers, and mortality in adult life [41,42].Second, the DBM can manifest at three levels for adolescents: 1) it occurs at the individual level through the simultaneous development of two or more forms of malnutrition (e.g., obesity with nutritional anemia or any vitamin or mineral de ciencies); 2) the DBM can occur at the household level (e.g., nutritional anemia in an adolescent with an overweight parent and diabetic grandparent); and 3) the DBM can be observed in the same community, region or country [4].
Loading [MathJax]/jax/output/CommonHTML/jax.js Especially, the stable rates of undernutrition in many LMICs coupled with the dramatic increases in overweight, obesity, and associated NCDs are placing heavy tolls on individuals, families, economies, and health-care systems [43].Third, after infancy, growth during adolescence is faster than any other period of life.On the one hand, there is an increase in height, peak bone mass, and body weight while on the other hand, the adolescent brain undergoes tremendous growth and development.Often referred to as the second window of opportunity for growth and development in the lifecycle, the adolescence offers a unique chance to address nutritional problems and develop healthy and long-lasting dietary and lifestyle habits [5].Fourth, given that approximately 16 million girls between the ages of 15 and 19 years enter motherhood every year across the globe, their nutritional status is important not only for their health but also for the health of their new-born as well as the family [44].Finally, good nutrition is one of the prerequisites for effective learning and vice versa [5,6].During the past two decades, public health research has shown the effects of social determinants of health, especially about the powerful and interactive effects of nutrition on one hand and brain functions, cognitive development and educational performance on the other hand, about disparities in each of these exacerbating the other, and how these disparities accumulate over life-cycle and generations [45].
Several evidence-informed actions exist to address adolescent nutrition.The school-based adolescent nutrition interventions can be broadly identi ed as 1) promoting healthy diets through education; 2) providing additional micronutrients through forti cation of staple foods and targeted supplementation; 3) managing acute malnutrition; 4) promoting physical activity; and 5) providing access to a safe environment and hygiene [44,45].[15].A systematic review of 18 studies on school feeding interventions found bene cial effects in terms of gained weight among the participants from lowerincome countries, and improved performances in cognitive tasks [9].On the other hand, a systematic review of six school-based nutritional supplements interventions found no evidence for reducing the reinfection rates of species-speci c soil-transmitted helminth infections and physical wellbeing of schoolage children between the age of 4 and 17 years [18].These single risk domain interventions fail to recognize that multiple lifestyle risk behaviors in adolescents co-occur as clusters and track into adulthood [51].It is also possible that discrete interventions that are not coordinated could be ineffective [52].Furthermore, when interventions operate in isolation they often lack su cient buy-in, training, and delity and are less likely to be sustained [53].Given the limited availability of funding for prevention and treatment interventions for adolescents, the Lancet Commission on Adolescent Health [5] and WHO's Global Accelerated Action for the Health of Adolescents guideline [47] highlight the necessity of synchronized prevention efforts to target multiple health risk behaviors in adolescents.
Several literature reviews and systematic reviews published in the last two decades examine the effectiveness of multi-component school-based health and nutrition interventions [20 − 27].A crossnational Cochrane review of 67 clustered randomized control trial (CRCT) studies on the effectiveness of HPS initiatives observed positive improvements in BMI, physical activity, and nutrition of the participants in a few studies [23].In another systematic review of 11 multi-strategy nutrition education interventions, four studies reported signi cant improvements in anthropometric measures and nine studies showed signi cant changes in dietary intakes [26].In a scoping review of seven studies on DBM, two schoolbased DBM intervention studies reported a modest reduction in thinness and no impact on overweight [54].Furthermore, recent research on interventions targeting multiple risk behaviors in school settings also suggests that by improving health outcomes, these programs can also enhance educational outcomes such as student attendance, school engagement, classroom behavior, mood, concentration, memory, standardized test scores, grade point average, grade advancement, and high school completion [55 − 59].However, the impact of multi-component school-based nutrition interventions on academic outcomes and cognitive development is modest [22].Evidence on the involvement of family or community in school-based health interventions is mixed [23].Overall, evidence suggests that comprehensive, multicomponent school-based interventions hold greater potential in promoting and supporting positive health behavior changes in the long-term than single-component nutrition interventions.
Although multi-component school-based nutrition interventions are promising, there are several gaps in the available evidence.First, most of the multi-component school-based health and nutrition interventions focused on general health and wellbeing, healthy eating, and physical activity and lacked attention to multiple forms of malnutrition [23].Second, these reviews have not examined which components of the package or the characteristics of the context that contributed to the reported effect.Third, many of the above-mentioned literature on multi-component school-based health intervention does not focus only on adolescents and includes child-adolescent binomial.This is a problem because it combines the two life Loading [MathJax]/jax/output/CommonHTML/jax.js stages into one and tends to neglect the unique health and development challenges of adolescents.Fourth, most of the studies included in these reviews come from high-income countries.Thus, little is known about the impacts of multi-component interventions on speci c nutrition and educational outcomes of adolescents in LMICs.Finally, previous reviews of multi-component school-based interventions are out-dated, with the most recent review published in 2015 [23], thus do not re ect all of the currently available evidence.Therefore, an updated and re ned synthesis of evidence on schoolbased nutrition interventions that target multiple forms of malnutrition and educational outcomes of adolescents, engage students, families, and communities and enable education, health and nutrition, and other agencies to synergistically improve nutritional status and education outcomes of all adolescents, is warranted.
In this context, our review will help advance the application of recommendations noted in the Lancet Commission on Adolescent Health [5], WHO's Global Accelerated Action for Health of Adolescents [47], and Child and Adolescent Health Volume of the third edition of Disease Control Priorities [6] advocate for integrated multi-component school-based health and nutrition approaches.Our review will contribute to the formulation of future programs to address the immediate and growing needs of school-going children as well as approaches to link schools, families, and the wider community through such interventions.
Further, the ndings of this review should help policy-and program-makers, researchers and practitioners, government and non-government agencies operating in health and education domains, to develop and

Figure 1
Figure 1 shows the conceptual framework focusing on adolescent-speci c nutrition interventions to guide our review.To organize and synthesize the existing body of knowledge on interventions addressing multiple forms of malnutrition in adolescents, our conceptual framework revolves around risk factors, potential interventions to prevent malnutrition and manage risk factors, and outputs and impacts at the individual, community, and societal levels.Methods/design Aims of the Review Loading [MathJax]/jax/output/CommonHTML/jax.js

4 .
Studies involving interventions for one or more of the following: interventions to promote healthy diets, interventions promoting physical activity, nutrition education, school feeding, micronutrient supplementation, managing acute nutrition problems, prevention, and management of overweight, obesity, or anemia, school gardens, and access to safe environment and hygiene including WASH interventions.
AbbreviationsBody Mass Index 3. Observational studies including cohort, case-control, and cross-sectional designs, 4. Editorial commentaries, opinions, and review articles, 5. Clinical treatments/interventions targeted towards individuals with speci c medical conditions such as programs intended for underweight, overweight, or obese adolescents, .Studies describing nutrition and/or educational interventions without linkage to speci c outcome/s, and 7. Studies of educational interventions focusing only on educational outcomes (e.g., school or classroom participation, classroom environment, teacher performance, and so on).
[50]e interventions can be broadly classi ed into two categories: 1) discrete single-component interventions; and 2) multi-component interventions with a focus on one or more determinants of nutrition status.Single-component interventions include obesity prevention, anemia prevention, and micronutrient supplementation whereas the multi-component interventions integrate multiple aspects of adolescent nutrition into a single intervention.The most widely recognized example of the multi-component school-based health and nutrition intervention is WHO's Health Promoting Schools (HPS) framework[46]which recognizes the link between health, nutrition, and education and encourages a whole school approach to improving health and educational outcomes.This framework describes six key pillars of HPS: 1) healthy school policies; 2) healthy school physical environments; 3) healthy school social environments; 4) health skills and education curriculum; 5) links with parents and school community, and 6) access to school health services.Individual countries have also developed their interpretation of the HPS concept and adapted it to their own needs and resources.For example, in Canada and the USA, the HPS is known as the 'Comprehensive School Health Program' model[47 − 49].In many LMICs, school-based nutrition programs, consisting of multi-component interventions including promoting healthy eating, less sedentary behavior, and more physical activity have been increasingly implemented worldwide since WHO launched the Nutrition-Friendly School Initiative in 2006 to address the multiple forms of malnutrition among school-aged children[50].Several systematic reviews of single-component interventions on high-income and/or LMICs suggest promising but modest evidence of an effect, with these reviews examining a range of interventions such as school feeding, nutrition education, obesity prevention, physical and activity[9 − 19].For example, a Loading [MathJax]/jax/output/CommonHTML/jax.js systematic review of 50 school-based obesity prevention interventions found signi cant differences between groups on BMI and BMI z − score