Medical nutrition therapy strategies for type 2 diabetes in Western and African contexts: a comparative scoping review protocol

Abstract

Introduction

Type 2 diabetes (T2D) is a growing global public health challenge, with a rapidly increasing burden in sub-Saharan Africa. Medical nutrition therapy (MNT) is a cornerstone of T2D management; however, its design, delivery and implementation vary across health systems, cultural contexts and resource environments. Most synthesised evidence and guideline development originate from Western settings, while MNT approaches in African contexts remain heterogeneous and less systematically characterised. This scoping review aims to map and compare MNT strategies for T2D across Western and African contexts.

Methods and analysis

This scoping review will follow the Arksey and O’Malley framework and its enhancements, aligned with Joanna Briggs Institute guidance. Reporting will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Searches will be conducted in PubMed, Embase, CINAHL, Scopus, CABI Global Health and African Journals Online, supplemented by grey literature and citation searching. Eligible sources will include studies and programme reports describing MNT interventions for adults with T2D published between 2000 and 2025 in Western or African settings. Eligibility will be defined using the Population–Concept–Context framework. Two reviewers will independently screen studies and extract data using a standardised, framework-informed charting form based on the Consolidated Framework for Implementation Research (CFIR) and the Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework. Data will be synthesised using descriptive numerical summaries, framework-informed thematic synthesis (deductive coding with inductive refinement), and comparative evidence matrices.

Ethics and dissemination

This review will use publicly available data and does not require ethical approval. Findings will be disseminated through peer-reviewed publication, conference presentations and stakeholder-oriented knowledge translation activities to inform culturally relevant, context-appropriate and implementation-ready MNT strategies across diverse health system settings.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• The review follows established scoping review methodology (Arksey and O’Malley framework, Joanna Briggs Institute guidance) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) reporting standards.

• Use of dual independent screening and data extraction enhances methodological rigour and reduces selection bias.

• Integration of Consolidated Framework for Implementation Research (CFIR) and Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) frameworks provides a structured approach for data charting and synthesis across heterogeneous studies.

• Comprehensive searches across multiple databases and grey literature sources increase coverage of diverse evidence.

• As a scoping review, no formal risk-of-bias assessment or quantitative synthesis will be conducted, and findings will depend on reporting quality of included studies.

Background

Type 2 diabetes (T2D) is a growing global public health challenge, affecting an estimated 537 million adults worldwide and projected to reach 783 million by 2045.^{1 2} The burden is increasing across all regions, with sub-Saharan Africa experiencing one of the fastest growth rates, where cases are expected to more than double due to urbanisation, demographic changes and shifts in diet and physical activity.^{1 3} T2D contributes substantially to morbidity, mortality and healthcare costs, placing sustained pressure on health systems. Effective management requires integrated clinical and behavioural strategies, including nutrition therapy as a core component. Medical nutrition therapy (MNT), an evidence-based, individualised approach delivered by trained professionals, has been shown to improve glycaemic control and cardiometabolic outcomes and is recommended as a foundational element of diabetes care.⁴,⁶

In many Western health systems, MNT for T2D is supported by established clinical practice guidelines, structured diabetes self-management education and support programmes, reimbursement mechanisms and a trained dietetics workforce.^{4 5 7} Common approaches include carbohydrate management, dietary pattern-based strategies such as Mediterranean and Dietary Approaches to Stop Hypertension (DASH)-style eating patterns, portion-control frameworks and structured behaviour change techniques such as goal setting and self-monitoring.^{5 6} Delivery formats range from individual counselling and group education to technology-assisted models, including telehealth and digital self-monitoring tools.⁵,⁷ In these settings, MNT is typically implemented as a defined clinical service within formal health system structures.

In contrast, MNT delivery in many African contexts occurs within more resource-constrained and heterogeneous health systems. Access to trained nutrition professionals, structured education programmes and reimbursement mechanisms is often limited, and diabetes care is frequently integrated into broader chronic disease services.^{3 8} Nutrition interventions are commonly adapted to local food environments, including staple foods, seasonal availability, household food insecurity and cultural dietary practices, as well as varying literacy levels.^{8 9} Approaches such as task-shifting to community health workers, group-based education, culturally tailored food substitutions and simplified visual tools are frequently reported.⁸,¹⁰ However, these strategies are not consistently described, classified or evaluated using standardised frameworks, limiting comparability and knowledge transfer across settings.

Study rationale

Although the clinical effectiveness of MNT in T2D management is well established, most guideline development and synthesised evidence are derived primarily from Western populations and health systems.^{5 6} Existing reviews have largely focused on the effectiveness of specific dietary patterns or nutrient strategies, with limited attention to how MNT interventions are designed, delivered, implemented and adapted across diverse contexts. As the global burden of diabetes continues to rise across Africa and among culturally diverse populations, there is increasing recognition of the need for culturally responsive, contextually appropriate and resource-feasible nutrition care models.^{1 8}

To our knowledge, no scoping review has systematically mapped and compared MNT strategies for T2D management across Western and African contexts. Key elements remain insufficiently characterised, including intervention components, delivery models, provider roles, cultural adaptations, implementation processes and methods used to assess dietary adherence. In addition, heterogeneity in intervention design, reporting practices and implementation environments presents challenges for synthesis using traditional systematic review approaches. A scoping review is therefore appropriate to map the range and characteristics of available evidence, clarify key concepts and identify knowledge and implementation gaps.¹¹,¹³ This review will generate a structured, cross-context evidence map of MNT strategies to support comparison, adaptation and future implementation research.

Study objectives

The objective of this scoping review is to systematically map and compare MNT strategies used for the management of T2D in Western and African contexts.

The specific objectives are to:

1. Identify and categorise the types of MNT strategies used in adults with T2D across Western and African settings.

2. Describe and compare key characteristics of MNT interventions, including dietary approach, counselling content, delivery modality, provider type, intensity and duration and behaviour change components.

3. Examine how dietary adherence and related nutrition outcomes are assessed, including tools and indicators used.

4. Summarise reported clinical and implementation outcomes as well as contextual barriers and facilitators influencing MNT delivery and uptake.

5. Identify knowledge and implementation gaps to guide future research and cultural adaptation of MNT programmes.

Methods and analysis

Conceptual framework

This scoping review is guided by an implementation-oriented conceptual framework that integrates constructs from the Consolidated Framework for Implementation Research (CFIR) and the Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework. The combined use of these frameworks enables a structured and transparent examination of how MNT interventions are designed, delivered and evaluated across diverse health system and cultural contexts.

CFIR is used to characterise the contextual and implementation determinants that shape MNT delivery. It provides a comprehensive structure for examining intervention characteristics (eg, dietary strategies and counselling components), outer setting factors (eg, food environments, policy context and resource availability), inner setting features (eg, health system infrastructure and workforce capacity), characteristics of individuals (eg, patient needs, cultural practices and literacy) and implementation processes (eg, training, adaptation and delivery strategies) that influence how MNT interventions are operationalised.¹⁴ In this review, CFIR domains will guide the classification of contextual and implementation-related variables and support cross-context comparison between Western and African settings.

RE-AIM complements CFIR by providing a framework to capture intervention outcomes and implementation impact relevant to public health translation. Specifically, RE-AIM domains will be used to extract and synthesise information on reach (who is served), effectiveness (clinical and behavioural outcomes such as glycated haemoglobin and dietary change), adoption (uptake by providers or sites), implementation (fidelity, cost and delivery consistency) and maintenance (sustainability and scale-up potential).¹⁵ This enables systematic assessment of how MNT strategies perform across contexts.

The integration of CFIR and RE-AIM enables simultaneous examination of (1) contextual determinants and implementation processes and (2) intervention outcomes and scalability. This dual perspective is particularly important for this review, which aims to compare not only the components of MNT interventions but also how they are adapted, delivered and sustained across settings with differing resources and health system structures. These frameworks directly informed the development of the data charting form, variable selection, and analytic approach. During data extraction, study characteristics and intervention features will be mapped to CFIR domains, while reported outcomes and implementation indicators will be aligned with RE-AIM dimensions. Findings will be synthesised using a framework-informed thematic approach and presented in comparative matrices to identify patterns, variations and evidence gaps across contexts. The integrated conceptual model guiding this review is presented in figure 1.

Figure 1. Conceptual framework for comparative analysis of MNT strategies. Conceptual framework guiding the comparative scoping review of MNT strategies for T2D across Western and African contexts. The framework integrates CFIR domains, an MNT intervention component layer and RE-AIM outcome domains to guide data extraction and cross-context comparison. CFIR, Consolidated Framework for Implementation Research; CHW, community health worker; MNT, medical nutrition therapy; RE-AIM, Reach, Effectiveness, Adoption, Implementation and Maintenance.

Protocol design

This scoping review will follow the methodological framework proposed by Arksey and O’Malley,¹¹ refined by Levac et al,¹⁶ and updated in accordance with Joanna Briggs Institute (JBI) guidance for scoping reviews.¹³ Reporting will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines (online supplemental appendix 1).¹²

Scoping reviews conducted under this framework proceeds through six stages: (1) identifying the research question; (2) identifying relevant studies; (3) selecting studies; (4) charting the data; (5) collating, summarising and reporting the results and (6) consulting stakeholders.^{11 16} The protocol has been registered with the Open Science Framework (OSF; Registration DOI: 10.17605/OSF.IO/NP47A). The review will be conducted from April 2026 to December 2026, encompassing study identification through data synthesis.

Stage 1: Identifying the research question

The research questions were developed a priori in consultation with the research team and relevant stakeholders and were guided by the Population–Concept–Context (PCC) framework.^{11 13 16} The population of interest is adults with T2D, the concept is MNT strategies, and the context includes Western and African settings.

The primary research question is: How do MNT strategies for T2D differ in their design, delivery and outcomes across Western and African contexts?

The secondary research questions are:

1. What types of MNT strategies are used, and how do their key components and delivery models differ across settings?

2. What contextual and implementation factors influence the design and delivery of MNT interventions?

3. What clinical, behavioural and implementation outcomes are reported, and how are they measured?

4. What gaps exist in the evidence to inform culturally relevant and context-appropriate MNT strategies?

Stage 2: Identifying relevant studies

Search strategy

The search strategy was developed collaboratively by the research team and a health sciences librarian at the University of Arizona. The review will follow the JBI three-step search approach for scoping reviews.¹³

First, an initial limited search of PubMed was conducted to identify relevant articles on MNT for adults with T2D. Titles, abstracts, keywords, and index terms from relevant records were analysed to refine search terms and controlled vocabulary.

Second, a comprehensive search strategy was developed for PubMed (National Center for Biotechnology Information) and will be adapted for Embase (Elsevier), CINAHL Plus (EBSCOhost), Scopus (Elsevier), CABI Global Health (EBSCOhost) and African Journals Online. Search terms combine controlled vocabulary (eg, MeSH terms) and free-text keywords to capture studies addressing the population (T2D) and the concept (MNT). Broad terminology will be used to ensure comprehensive retrieval of nutrition-centred interventions described under varied terms.

Geographic context will not be restricted at the search stage. Classification of studies as Western or African will occur during screening based on predefined regional criteria to avoid exclusion of relevant multinational or misclassified studies.

The full PubMed search strategy is provided in online supplemental appendix 2. Search strategies will be adapted appropriately for each database.

Third, backward and forward citation searching of included studies will be conducted to identify additional relevant sources.

Grey literature searches

Grey literature searches will follow a structured approach using predefined source lists and keyword combinations. Sources will include guideline repositories and reports from international and governmental organisations (eg, WHO, International Diabetes Federation, ministries of health), non-governmental organisations and theses or dissertations. Grey literature sources and search processes will be documented to enhance transparency and reproducibility.

Eligibility criteria (PCC framework)

Eligibility criteria will be defined using the PCC framework recommended for scoping reviews.^{11 13 16}

Population

Adults (≥18 years) with T2D receiving MNT interventions. Studies focused exclusively on type 1 diabetes, gestational diabetes or paediatric populations will be excluded.

Concept

MNT as a primary component of diabetes management, including structured nutrition counselling, dietary education, meal planning, culturally tailored dietary approaches, and nutrition-centred lifestyle interventions. Studies in which nutrition is not a central intervention component will be excluded.

Context

Studies conducted in Western and African regions, defined using standard geographic regions as classified by the United Nations Statistics Division¹⁷ (full country list provided in online supplemental appendix 3).

Studies published between 1 January 2000 and 31 December 2025 will be included. This timeframe reflects the period during which MNT became established as a defined evidence-based clinical service within major nutrition and diabetes care guidelines.¹³ No language restrictions will be applied. Where necessary, translation tools or multilingual team support will be used for screening and data extraction.

Types of sources

Experimental, quasi-experimental, observational, qualitative, mixed-methods, programme evaluations, clinical guidelines and relevant grey literature will be included. Commentaries, editorials and reviews will be excluded.

Stage 3: Study selection

All records identified through database and grey literature searches will be imported into reference management software EndNote 2025 (Clarivate Analytics, Philadelphia, PA, USA), where duplicates will be identified and removed. Each record will be assigned a unique identification number to facilitate tracking throughout the review process, and source type (eg, peer-reviewed article, guideline, grey literature) will be recorded. Deduplicated records will then be exported to Rayyan (Rayyan Systems, Cambridge, Massachusetts, USA) for screening.¹⁸

Study selection will occur in two stages using predefined PCC eligibility criteria. In Level 1 (title and abstract screening), two reviewers will independently screen records as ‘include’, ‘exclude’ or ‘maybe’. Screening criteria will be pilot-tested on approximately 20 records to ensure consistent interpretation and application. Non-English records will be screened using translation tools where necessary. Titles without abstracts that appear potentially relevant will be classified as ‘maybe’. Disagreements will be resolved through discussion, with unresolved conflicts adjudicated by a third reviewer.

Records classified as ‘include’ or ‘maybe’ will proceed to Level 2 (full-text screening). Full texts will be assessed independently by two reviewers using a structured screening form based on predefined PCC eligibility criteria. The full-text screening form will be pilot-tested on a subset of studies and refined if necessary. Reasons for exclusion at the full-text stage will be recorded systematically. Disagreements will be resolved through discussion or consultation with a third reviewer.

The study selection process will be documented using a PRISMA-ScR flow diagram, reporting numbers of records identified, screened, excluded and included, along with reasons for exclusion at the full-text stage.¹² The search results will be considered final on the date of the last database search.

Stage 4: Data charting

Data will be charted using a standardised, pilot-tested extraction form developed by the research team and informed by JBI guidance and implementation science frameworks (CFIR and RE-AIM).¹³,¹⁵ Two reviewers will independently extract data, with discrepancies resolved through discussion and, if necessary, adjudication by a third reviewer. The charting form will be piloted on a subset of included studies and refined iteratively to ensure clarity and consistency. Data extraction decisions and coding rules will be documented to enhance transparency and reproducibility.

Extracted variables will encompass study characteristics, population attributes, MNT intervention components, delivery and workforce features, implementation context, outcomes, adherence measurement and scale-up indicators to enable structured cross-context comparison between Western and African settings. Variables were mapped a priori to CFIR and RE-AIM domains to support theory-informed synthesis. The data charting framework is summarised in table 1, and the full extraction form is provided in online supplemental appendix 4.

Table 1. Data charting framework (CFIR+RE AIM informed).

Domain	Variable categories	Examples of extracted items
Study identification	Bibliographic and design details	Author, year, country, region (Western/African), study design, setting, source type
Population	Participant characteristics	Sample size, age, sex, T2D criteria, SES indicators, literacy, food insecurity
MNT intervention components	Core nutrition strategy	Dietary approach, named diet model, cultural adaptations, staple substitutions, meal planning tools
Delivery model	Format and exposure	Individual/group, in-person/digital, frequency, duration, total length, follow-up
Provider and workforce (CFIR—inner setting)	Delivery agents	Provider type, task-shifting, training, multidisciplinary involvement
Behaviour change techniques	Behavioural strategies	Goal setting, self-monitoring, problem solving, social support, motivational interviewing
Implementation features (CFIR—process)	Implementation characteristics	Adaptations, cultural tailoring, literacy adaptation, materials, fidelity, barriers, facilitators
Context factors (CFIR—outer setting)	System and environment	Food environment, affordability, policy linkage, health system capacity
Outcomes (RE-AIM—effectiveness)	Clinical and behavioural	HbA1c, weight, BP, diet quality, intake change, knowledge, self-efficacy
Adherence measurement	Adherence methods	Recall, FFQ, diaries, app logs, adherence definitions and thresholds
Scale and sustainability (RE-AIM)	Implementation impact	Reach, adoption, cost, sustainability, scale-up potential
Reviewer notes	Interpretation	Key findings, implementation insights, transferability notes

BP, blood pressure; CFIR, Consolidated Framework for Implementation Research; FFQ, food frequency questionnaire; HbA1c, glycated haemoglobin; MNT, medical nutrition therapy; RE-AIM, Reach, Effectiveness, Adoption, Implementation, Maintenance; SES, socioeconomic status; T2D, type 2 diabetes.

Stage 5: Collating, summarising and reporting the results

Data synthesis will be conducted following completion of data charting and in accordance with established scoping review guidance.^{11 13 16 19} The objective of synthesis is to systematically map and characterise the range, features and distribution of MNT strategies rather than to estimate pooled intervention effects.

First, extracted data will be summarised using descriptive numerical analysis, including counts and distributions of studies by year, geographic region, study design, intervention type, delivery model and provider category. These summaries will be presented in tables and figures to describe the landscape of available evidence.

Second, a framework-informed thematic synthesis will be conducted, guided by the integrated conceptual framework (CFIR and RE-AIM). Coding will follow a structured, iterative process. An initial coding framework will be developed deductively based on pre-specified domains (eg, intervention components, delivery models, contextual factors, implementation features and outcomes). During analysis, codes will be refined inductively to capture emergent patterns and concepts not fully represented in the initial framework. Coding will be conducted by two reviewers, with discrepancies resolved through discussion to ensure consistency and transparency.

To address heterogeneity across study designs, contexts and reporting approaches, data will be categorised and analysed according to key dimensions, including intervention type, delivery model, provider characteristics and geographic context (Western vs African settings). A comparative evidence matrix will be developed to systematically map MNT strategies, implementation features and outcomes across contexts, enabling identification of patterns, similarities and differences.

Findings will be synthesised using a narrative, framework-aligned approach, rather than quantitative pooling, consistent with scoping review methodology. The synthesis will integrate descriptive summaries and thematic findings to highlight recurring themes, context-specific adaptations, implementation considerations and evidence gaps.

Consistent with scoping review guidance, formal risk-of-bias assessment and meta-analysis will not be conducted.^{11 13} Variability in reporting and study design will be documented and considered in the interpretation of findings. This structured, framework-informed synthesis approach enhances methodological transparency, reproducibility and comparability across heterogeneous evidence sources. By explicitly integrating CFIR and RE-AIM domains throughout data extraction and analysis, the review ensures a systematic and theory-driven interpretation of MNT strategies across contexts.

Stage 6: Stakeholder consultations

Consistent with scoping review methodology, stakeholder consultation represents an optional knowledge translation stage.^{11 16} To enhance the relevance, contextual interpretation and applicability of the findings, key stakeholders will be consulted following preliminary synthesis. Stakeholders may include dietitians and nutrition professionals in Western and African settings, diabetes educators, public health practitioners and programme collaborators.

Consultation will aim to contextualise findings, identify practical considerations for implementation across settings and highlight issues related to transferability and scale-up. Activities may include structured feedback meetings or written feedback on summary results. Feedback will be summarised descriptively to inform interpretation but will not constitute primary qualitative research or formal data collection. Consultation will not influence study eligibility decisions or data extraction procedures. Insights may inform knowledge translation outputs and future refinement of the comparative framework.

Ethics and dissemination

This scoping review will synthesise evidence from publicly available published and grey literature sources and will not involve human participants, individual-level data or confidential information. Accordingly, ethical approval is not required.

Findings will be disseminated through peer-reviewed publication and presentations at national and international conferences in nutrition, diabetes care, global health and implementation science. Results will also be shared with professional, clinical and policy audiences through academic seminars, stakeholder briefings and knowledge translation activities. Framework-aligned evidence maps and summary tables describing MNT strategies, delivery models and implementation characteristics across Western and African contexts will be developed to support cross-context interpretation and application. Where appropriate, summary outputs will be shared with practitioner and public health networks to facilitate broader dissemination.

Any protocol amendments will be documented and updated in the OSF registration record.