Dish swap across a weekly menu can deliver health and sustainability gains

A weekly canteen menu comprising 15 dishes (3 dishes × 5 days) has 1.4 million unique configurations. Here food choice was monitored over four weeks ( ~ 5,000 meals) in a UK university residence. Without students noticing, mathematically optimized menus achieved 30.7% and 6.3% reductions in carbon footprint and saturated fatty acid intake, respectively. This demonstrates the potential of strategic menu manipulation to benefit health and the environment, without the need for recipe changes.