Using implementation science to promote evidence-based nutritional care in healthcare settings: A mixed-methods systematic review.

Background: Up to half of hospital inpatients are malnourished, a condition that prolongs recovery, increases complications and raises healthcare costs. Although evidence-based nutritional care can mitigate these effects, its routine implementation remains inconsistent. Objective: To synthesise and evaluate current evidence on the implementation and the clinical effectiveness of strategies designed to promote evidence-based nutritional care practices within healthcare settings. Methods: A mixed-methods systematic review followed the Joanna Briggs Institute guidelines. Fifteen databases were searched for studies published between January 2015 and January 2025 that evaluated implementation strategies targeting evidence-based nutrition care for any patient or healthcare professional group. Two reviewers independently screened records extracted data and applied the Mixed-Methods Appraisal Tool. Because study designs, contexts and outcome metrics varied, findings were integrated narratively using the Consolidated Framework for Implementation Research, the Expert Recommendations for Implementing Change taxonomy and the Implementation Outcomes Framework. Results: Twenty-nine primary studies involving 1624 healthcare professionals and 13,523 patients were included. All interventions were multifaceted and tailored to the context. The most frequent components were staff education (97 %), audit with feedback (93 %), stakeholder engagement structures (62 %), and adaptations to electronic or physical workflows (28 %). Principal barriers experienced by healthcare professionals comprised scarce resources, fragmented communication, inadequate infrastructure, and knowledge deficits; key facilitators were visible leadership, standardised communication tools, iterative planning, and a strong evidence base. Fidelity of intervention delivery by healthcare professionals was consistently high (median ≥ 80 %); acceptability exceeded 70 % in all studies that assessed it, and feasibility was rated favourably. Where measured, penetration and sustainability were moderate but positive. Service outcomes improved across settings, including earlier initiation of nutrition therapy, greater dietary adequacy, and fewer treatment interruptions or nutrition-related complications. Patient-level benefits comprised reduced weight loss, improved nutritional status, better health-related quality of life, and higher satisfaction. Conclusion: Context-sensitive, multifaceted implementation strategies, particularly those coupling education, audit-feedback, leadership engagement, and system redesign, can improve the uptake and impact of evidence-based nutritional care. Future studies should employ standardised frameworks, extended follow-up, and rigorous evaluation designs to assess sustainability and inform large-scale implementation. PROSPERO registration: Not registered.