Strategic menu optimization could reduce carbon emissions and saturated fat consumption: a simulation modelling study of UK hospital inpatient meals.

Interventions to improve nutritional quality and environmental sustainability often rely on 'nudging', education or (dis-)incentive-based measures. As part of the Transforming UK Food Systems Programme (Flynn ., 2025), we recently proposed a 'fourth' approach that complements these strategies-whereby dishes are swapped across a weekly menu to alter daily inter-dish competition, and thus choice architecture-and validated its effectiveness in a university canteen where meals are pre-paid for the whole year. As a second step in assessing the potential of our approach, we modelled strategic menu swaps in an alternative public procurement setting. Eleven weekly inpatient menus were sampled opportunistically from National Health Service hospitals across the UK and combined with responses from an online food-choice task ( = 550, 50 participants per region). Expected reductions in weekly carbon footprint and saturated fatty acid (SFA) intake were then calculated under mathematically optimized menus, targeting each outcome independently and simultaneously. Targeting a single variable resulted in a 12.7-29.3% reduction in carbon footprint and a 6.5-31.5% reduction in SFA intake. Joint optimization achieved a 9.1-29.3% and a 5.0-26.5% reduction, respectively. We discuss key next steps for real-world implementation in hospitals and other catered environments such as schools.This article is part of the theme issue 'Transforming terrestrial food systems for human and planetary health'.