Health and Nutrition Interventions to Prevent Childhood Overweight and Obesity: A Systematic Review

1. Introduction

Overweight and obesity (OW + Ob) are chronic multifactorial conditions with genetic, environmental, and lifestyle determinants that pose significant health risks including type 2 diabetes, hypertension, dyslipidemia, and cardiovascular diseases [1,2]. The main factors related to OW+ Ob include physical inactivity and consumption of energy-dense foods [3], which present modifiable opportunities for prevention and treatment [4].

The prevalence of obesity in school-aged children has increased, mirroring the global trend, with the World Obesity Federation projecting a substantial increase by 203 [5,6]. This surge is associated with nutritional transition [7,8], marked by the availability of low-cost processed foods, increased fast food consumption, reduced home food preparation time, and heightened exposure to sedentary-inducing products [9,10]. In Latin America, particularly Mexico, Argentina, and Chile, 30% of those aged 5–19 years are affected [11].

Body image and parental perceptions significantly influence children’s access to care [12,13]. Early habits often persist in adulthood, underscoring the need to modify obesogenic environments for children's long-term health [10,13]. Understanding the causal factors is crucial to address the high prevalence of obesity in school-aged children. Education promoting healthy habits, early weight gain detection, and targeted interventions is essential [14].

Public health interventions for childhood obesity vary, with single or multicomponent approaches targeting areas such as education, physical activity, and nutrition policy [9]. Previous reviews have focused on specific settings, such as homes or schools [15,16], yielding mixed findings. Recent systematic reviews have highlighted challenges in evidence quality, intervention group comparisons, and study design clarity [15,16,17].

Additionally, recent meta-analyses have highlighted that while school-based interventions show small but significant benefits on BMI in children aged 5–11 years, these benefits may not be equally distributed across gender and social groups. Evidence suggests interventions tend to be more effective in boys, and there is limited information on whether they reduce health inequities as measured by the PROGRESS framework [18]

A specific review in Mexico underscores the effectiveness of multicomponent interventions combining physical activity, nutrition, and behavioral change to prevent and reduce childhood obesity. The authors emphasize methodological shortcomings, urging the scientific community to develop robust preventive and curative solutions [17].

This systematic review aimed to summarize essential elements in designing interventions for obesity in school-aged children, offering a critical evaluation to address knowledge gaps, despite a high volume of available studies. By informing future researchers, this review aims to guide the development of effective personalized programs for the Mexican school population.

2. Materials and Methods

This systematic review of interventions (SRI) adhered to the methodology proposed by the Cochrane Collaboration [18], and PRISMA statement were followed, with collaboration from trained personnel across five institutions. A team of two authors meticulously examined the compiled studies, assessing risk and quality while standardizing the criteria and fields of interest. Each author independently conducted a blind review of the scientific evidence and assessment measures.

The outcomes of this review serve as the cornerstone for the development of the Community Intervention of Integral Action for Children in Nutritious and Healthy Environments (INCAI in Spanish). The protocol for this review was approved by the Ethics, Biosafety, and Research Committees of the National Institute under Protocol CI:1791 1791 and was registered in PROSPERO: CRD4202454214.

Serch Strategy and Terms

A comprehensive search strategy spanned six digital databases (ScienceDirect, DOAJ, Scielo, EbscoHost, Redalyc, and PubMed), using the PICO framework [19]. Collaborating with authors from five academic institutions provides diverse perspectives. Derived from Rivera Dommarco et al.'s book chapter [20], the search criteria covered themes such as obesity, school-aged population, program design, implementation, and evaluation. Key terms were adapted to the MeSH definitions, accounting for synonyms and MeSH Tree Structures [19].

Search chains utilizing key terms with a PICO structure and Boolean operators were constructed. The inclusion criteria focused on community interventions aimed at enhancing health in local communities, guided by Trickett et al.'s definition [22]. The PICOS framework [23] directs criteria, emphasizing the impact of community interventions on overweight and obesity prevalence in school-aged children.

The reviewers independently evaluated abstracts and titles, prioritizing original articles, controlled cohort studies, and longitudinal studies in Latin America up to December 2023. Outcome measures included reduction in overweight or obesity prevalence, BMI z-score reduction, improved dietary habits, formation of healthy habits, and increased physical activity. This meticulous approach has ensured a comprehensive and diverse exploration of interventions for childhood obesity in the school context.

Data Extraction

Predefined data extraction forms were completed to record study characteristics. Each author was responsible for completing the forms, and the two authors/researchers reviewed and compared the extracts containing the following information:

I) General information: database; search string; PICO elements; Digital Object Identifier (DOI); author; year of publication; title; country; study design and type; language; identification of control or intervention group; total sample size; population evaluated.

II) Intervention details: diagnostic criteria for overweight or obesity, type of intervention (nutritional, physical activity, educational, mixed), study summary, duration of intervention (in months), intervention site, population included in the intervention, and intervention staff.

III) Outcomes: Changes related to the program, such as reduction of obesity components, changes in lifestyle, changes in diet, and changes in physical activity.

III) Results: Program-related changes, such as a reduction in obesity components, lifestyle changes, dietary changes, and physical activity changes.

Strategy for selection and Assessment

After compiling and standardizing the articles using extraction forms, a thorough assessment was conducted using SPSS with group string functions and simple descriptive analyses in the exploratory review.

Dictionaries were created to standardize variable definitions, covering journal names, DOI, country, intervention duration, and evaluated population. A code was devised to associate each country with its region using an international classification system. Mexico was classified separately because of its significant relevance, and other classifications included North America, Latin America, the Caribbean, Asia Pacific, Europe, the Middle East, North Africa, and Southern Africa [24].

For critical assessment, the Mixed Methods Appraisal Tool (MMAT) version 18 was employed [25], utilizing a two-phase scoring system involving base filtration and specific filtration based on the study methodology. The criteria included screening/diagnostic methods and quantitative methods (controlled and non-randomized) [26].

Studies that met the inclusion criteria and passed methodological assessments were independently reviewed by two authors. Key participant and intervention characteristics were summarized using standard templates, and narrative synthesis was employed to report data on favorable or unfavorable outcomes. This meticulous approach ensured a comprehensive and robust evaluation of selected studies on childhood obesity interventions in the school context.

3. Results

3.1. Description of Selected Studies

A total of 127 articles were initially collected, and after excluding 30 duplicates and articles without DOI, 97 articles remained (figure 1) [27]. The first exploration eliminated studies with a transversal or descriptive design and those describing the study protocols, resulting in a final set of 59 articles for further analysis. Articles published in English or Spanish within the past 11 years constituted the final selection for the systematic review.

Variables, such as intervention type, geographic location, language, and publication year, were examined. Most studies were conducted in North America, Europe, Latin America, the Caribbean, Asia Pacific, and Mexico. The selected studies described interventions with a median population of 2,124 participants and a median duration of 17.8 months.

After cleaning the database, additional filters were applied to identify the characteristics of interest. Critical evaluation using the MMAT led to the exclusion of studies that did not meet the methodological criteria or lacked relevant results. Articles were further discarded if they had unclear outcome measure descriptions, lacked critical methodological aspects, or described interventions of less than six months. The final selection of the analysis included 10 studies.

This review focused on articles that specifically addressed obesity in school-aged populations, including one or more interventions (physical activity, diet/nutrition, and socioemotional skills), which were conducted in the school environment, and included community-based components.

The primary measures in the 10 selected studies included reduction in the prevalence of overweight and obesity, reduction in z-score of BMI for age, improvement of dietary habits, promotion of healthy habits, and increase in physical activity. Eight studies were multicomponent, addressing both diet/nutrition and physical activity, while two focused solely on diet/nutrition without utilizing a control group. Three studies considered socioeconomic status (SES) and belonged to indigenous or minority groups. The median study duration was 22 months, ranging from eight–43 months). Four studies specifically considered SES, whereas two did not mention any of the specified characteristics.

Anthropometric measures, particularly height and weight for estimating BMI and nutritional status, were used in all 10 studies, with half utilizing reference values from the World Health Organization. Six studies included additional risk components such as waist circumference, and only one reported the measurement of biochemical markers to detect metabolic syndrome (Table 1).

Due to the specific inclusion criteria prioritizing studies in Mexico and Latin America and the focus on multi-component interventions, the limited number of studies obtained prevented the establishment of a meta-analysis. The heterogeneous results, combined with a lack of methodological rigor in some studies, may compromise the interpretation or lead to unreliable and inconsistent statistical synthesis.

3.2. Figures and Tables

Figure 1. PRISMA Flowchart

Figure 1. PRISMA Flowchart

3.3 Diet and Nutrition

The identified interventions predominantly utilized educational lessons, workshops, and sports clubs, focusing on diet/nutrition (D/N). Nine out of ten interventions were implemented within schools, with four including a consistent nutritionist presence. Health sector personnel included physicians, nurses, nutrition educators, and health professionals.

Parental involvement was a significant feature of the eight interventions with D/N components, and only two were extended to the broader community. The effects included an increased demand for healthier foods in school cafeterias, improved food availability, changes in unhealthy food consumption, increased vegetable consumption, and reduced consumption of high-fat snacks. Tarro [28], Bacardi [29], and Waters [30] focused on healthy food selection education, increased fruit and vegetable consumption, and decreased sugary and fatty snack consumption. Others, such as Safdie [31] and Long [32], have enhanced the school food environment by increasing healthy food availability, reducing high-calorie density foods and sugary beverages, and incorporating nutrition education.

Some studies, such as the Kids Nutrition and Fitness (KNF) program [33], provided extracurricular nutrition education, while Vazquez [34] and Scruzzi [35] focused on nutrition education through workshops, evaluating the impact on consumption before, during, and after intervention. Parental involvement and school environment modifications have emerged as promising aspects for success in reducing childhood obesity.

Flynn's study [36] underscored the significance of home interventions and family involvement in preventing obesity in children under five. Active engagement of adults, especially parents and teachers, is crucial for favorable outcomes such as weight reduction and obesity prevention. However, Morgan et al. [37] suggested the need for additional evidence, emphasizing the importance of primary studies detailing intervention designs and outcome measures to establish the value of caregiver involvement.

3.4. Physical Activity

In interventions incorporating physical activity components, physical education teachers played a central role in five of eight cases, with classroom teachers providing support. Only two interventions involved a leading health professional. Four interventions demonstrated positive effects on physical activity levels among school-aged children, emphasizing strength-building activities, additional physical education sessions, and improvements in sports and playground equipment.

All studies focused on interventions during regular school hours, with only one extending the activity to the home. Five studies involved parents, and two showed significant changes, increasing physical activity hours and reducing sedentary time, compared to the control groups.

All studies focused on interventions during regular school hours, with only one extending the activity to the home. Five studies involved parents, and two showed significant changes, increasing physical activity hours and reducing sedentary time, compared to the control groups.

In a review by Liu et al. [38], BMI variations were noted with physical activity; however, no significant differences were found between interventions with multiple components and those focusing on a single component. Ameryoun et al. [39] found that game-based interventions had a consistent but small effect on reducing BMI Z-scores, especially when combined with nutrition and education.

Bleich et al.'s review [40] highlighted that prioritizing physical activity sometimes reduced interventions in education and dietary components. Synthesizing evidence emphasizes the importance of various activities in obesity reduction programs. School-based interventions, particularly strength sports and active games, offer promising opportunities for study. Improving evidence in these areas can help identify effective strategies for reducing excess weight in early childhood.

3.5. Overweight and Obesity

Several studies, including those by Sadeghi [41], Bacardi [29], Tarro [28], and Vazquez [34], demonstrated significant reductions in obesity measures among school-aged children in their interventions compared to control groups. Safdie's [31] basic intervention showed the greatest reduction in the prevalence of overweight or obesity, dropping from 12.1% to 10.9%. Bacardi-Gascon noted a primary change in abdominal obesity percentage, decreasing from 20.6% to 15.2% [29].

However, Waters [30] and Centeio [42] reported decreased overweight and obesity proportions in both the intervention and control groups, complicating the attribution of results solely to interventions. Brown et al. [43] review suggested that combined physical activity and diet interventions in preschoolers reduce obesity risk and BMI-for-age Z-score. In 6–12-year-olds, physical activity interventions reduced BMI, Z-score, and overweight/obesity prevalence, but the difference was not statistically significant. Dietary interventions in this age group lacked conclusive evidence, whereas combined interventions reduced the BMI Z-score for age.

Cauchi et al. [44] reported small-to-modest impacts on anthropometric outcomes and childhood obesity reduction in most interventions, with no clear link between intervention components and effectiveness. A notable limitation of this review and others is the lack of methodological clarity, especially in statistical power calculations, hindering the precise interpretation of observed variations. Clearer reporting of methodological criteria is essential for a more accurate understanding of effective approaches to address childhood obesity.

3.6. Socioemotional Skills

Few studies have emphasized socioemotional skills and behavioral changes as success factors in treating childhood overweight and obesity. Giannin et al. [45] found that caregivers enrolled children for physical and mental health improvement, especially when medical issues, such as high blood pressure and probable diabetes, were identified. The caregivers acknowledged that small changes at home led to weight loss and habit changes, acting as a catalyst for further positive changes.

Waters et al. [30] and Vásquez et al. [34] integrated psychological aspects into their interventions. Waters included self-esteem promotion, whereas Vasquez included sessions with a psychologist to support behavioral changes related to diet and physical activity. These findings highlight the significance of addressing not only physical health, but also socioemotional well-being and behavioral modifications in effective childhood obesity interventions.

4. Discussion

Our analysis underscores the crucial role of intervention time in addressing childhood obesity and emphasizes its impact on program design and implementation. Among the studies analyzed, nine interventions occurred within the school environment during regular hours, with five extending hours and two involving community components.

Dividing treatments for overweight and obesity, as seen in other reviews, helps reduce result heterogeneity and prioritizes recommendations based on their effectiveness. The review by Long et al. highlights that a long intervention time does not guarantee effective adherence or reduction in obesity, suggesting the need for modifications when transitioning from short-to long-term interventions.

Effective interventions lasting between eight and nine months have proven successful in addressing childhood obesity. Strategies combining proper nutrition, promotion of fruit and vegetable consumption, water intake, and physical activity in schools over 4 to 12 months showed positive effects on maintaining or slightly improving BMI. However, the standardization of design and implementation remains a common need across studies.

Our findings align with global evidence that the effectiveness of obesity prevention interventions may differ across subgroups. As Palmer et al. [17] in 2025 showed in a re-analysis of 81 trials, interventions had greater impact on boys aged 5–11 and did not significantly affect inequities across other PROGRESS domains. These insights support the need for equity-sensitive design in future interventions, especially in Latin American contexts where social and economic disparities are profound.

In Mexico, the "Nutrition on the Go" strategy, which focuses on reducing the energy content of school breakfasts, including fruits and vegetables, and promoting physical activity and water consumption over six months, had a statistically significant effect on reducing the probability of shifting from overweight to obesity categories. This study also documented a decreasing effect of the shift from the normal to overweight categories during the intervention [45].

Long et al.'s study, emphasizing that a longer intervention (36 months) did not guarantee effective results, recognized the limited impact on BMI, potentially due to the extension of a short-term intervention without necessary modifications. In summary, intervention length is a critical factor and careful consideration, and adaptation are essential for effective and sustained outcomes in childhood obesity programs.

Interventions involving family and teachers had greater effects on both diet and physical activity, contributing to positive outcomes. This underscores the importance of collaborative programs that involve multiple stakeholders.

Addressing the Latino and/or Mexican population in the United States is increasingly crucial due to their heightened vulnerability to obesity, which is often tied to their social and economic environments.

Various techniques and theories, such as socio-ecological theory, theory of social education, and ecological methods for healthy habit formation, have been identified in interventions. This was particularly prevalent in programs aimed at instilling habits through education.

The focus on the school-aged population, specifically targeting ages eight to nine, highlights the segmentation of physical and learning activities. In the Mexican context, this corresponds to first-to third-year students in the first group and fourth-to sixth-year students in the second. However, the inclusion of different grades and ages in the assessed studies may limit the generalizability of their findings. Overall, these insights emphasize the importance of tailored approaches, collaboration, and cultural considerations when addressing childhood obesity.

Our study had some limitations, such as the potential lack of studies in certain regions or variability in methods for measuring intervention impacts, and the potential impact of the absence of controlled and randomized studies on the robustness of conclusions. Concerning the evidence, two studies did not include a comparison with a control group. However, these studies were included because of the type of information provided. Regarding the review processes, we consider that some effects could have been estimated using statistics and odds ratios. Nevertheless, this review focused on narrative analysis to identify design strengths for future strategies to be implemented in the design of an intervention program.

5. Conclusions

In this overview plenty of interventions were presented for the prevention of overweight and obesity in school-age children. Interventions aimed at preventing, controlling, or reducing obesity generally lack a multisectoral approach and integrated components. Providing dietary and nutritional education to the entire population is crucial for reducing the prevalence of non-communicable diseases by promoting healthy habits and behaviors.

Implementation of interventions requires collaboration between the health and education sectors, considering the influence of the social determinants of health. Recognizing and addressing obesogenic environments is particularly important. These considerations emphasize the need for methodological rigor, multi-sectoral approaches, and a comprehensive understanding of social determinants in designing effective interventions for childhood obesity.

Intervention policies to prevent obesity in schoolchildren should consider changes within the school environment itself through actions such as improving physical education classes and creating more aggressive nutritional policies. For a greater impact, the inclusion of parents and teachers, as well as government officials, communities, and civil society as elements of healthy lifestyles, as well as the development and well-being of society, is recommended.