Changing Nutrition Practice in Critical Care: Bridging Policy and Historical Context in the NHS

Introduction: Variation in critical care nutrition practice remains, despite strong evidence and international standards to guide providers. We asked: how does historical organisational context shape nutrition implementation in critical care? The goal was to generate insight for clinicians, managers, and policy makers seeking sustainable, context-sensitive practice improvement.


Methods: A longitudinal, multi-site case comparison study examined nutrition practice across three UK NHS critical care units between 1980–2020. We conducted 42 interviews and a documentary analysis. A qualitative, process-informed, thematic approach explored how workplace culture, professional norms, and external policy conditions interacted over time to shape practice.


Results: Seven interrelated themes explained how nutrition practices became embedded or changed over time, including: system-level policy influence; changing organisational circumstances; clinical leadership; the cumulative effects of past events; embedded beliefs and norms; routine patterns; and the persistence of hard-to-reverse practices.

Policy shaped conditions for improvement in contingent ways. Politically driven NHS service centralisation, funding decisions, and governance reform aligned with local leadership efforts and culture in some cases, enabling improvement. In others, disinvestment and the loss of clinical specialties created enduring constraints, including a reduced will to change. These legacies helped constitute, not just constrain, the environments in which change was later attempted. Implementation “failures” often reflected transitional periods within embedded systems, rather than resistance.


Conclusions: Effective improvement requires more than protocol roll-out. Context must be understood as dynamic, historically shaped, and structurally constrained. Sustainable change is more likely when units: 1) identify local beliefs and routines; 2) explore past change efforts; 3) recognise trusted influencers; and 4) adopt realistic timelines that stretch beyond typical project or audit cycles.

System-level actors must ensure time, leadership continuity, and aligned investment to avoid reinforcing structural inequities. These findings are transferable beyond nutrition to other critical care practice areas where history, culture, and policy intersect.