In the new study, published today in the International Journal of Behavioural Nutrition and Physical Activity, researchers asked cafeteria managers at six worksites across England to replace one meat-based lunch option with a vegetarian dish, while keeping the total number of main meal choices, prices and everything else the same. Customers were not told about the change, and meat options were still always available.
Over seven weeks, the intervention covered 26,170 meal sales across six sites. They found a 41% increase in the likelihood of customers choosing a vegetarian main meal during the intervention period.
Meals sold during the intervention were also healthier and more sustainable on average. They contained around 26 fewer calories – about one cup of tea with milk and a teaspoon of sugar, as well as lower levels of saturated fat and salt. The environmental footprint of meals also decreased, including a reduction of 160g CO2-equivalent per meal - roughly an 8.5% drop compared with baseline – alongside reductions in biodiversity loss, water pollution potential and water scarcity, based on ingredient-level estimates.
Importantly, the menu change did not negatively affect business performance. The researchers found no evidence of reduced revenue, fewer meals sold or increased food waste.
This is the first trial to test this type of availability intervention in workplace cafeterias. It included both office-based and manual labour workforces across manufacturing and logistics sectors, suggesting the approach is effective in diverse real-world environments.
Dr Elisa Becker, lead author and post-doctoral researcher in the Nuffield Department of Primary Care Health Sciences, said: ‘The findings show that small changes to food environments can have a big effect without requiring customers to make extra effort, read labels or use self-control. Instead of placing the burden on consumers, we found that simply offering more options that are better for health and the environment, shifts eating behaviour in a healthier and more sustainable direction.’
Interviews with cafeteria staff and customers found the change was generally seen as acceptable, non-intrusive and easy to implement. Initial staff concerns about customer dissatisfaction, extra workload and wasted food were not borne out by the sales and waste data.
The researchers say the findings have important implications for workplace food policy and for wider efforts to support healthier, lower-carbon diets. They argue that availability-based approaches could be scaled up in similar settings and may have a role in the government’s future food strategy for England.
The team are hoping to run similar simple menu change interventions in other industry settings and are always looking for new partners who would like to make a positive change towards health and sustainability. If you’re interested in taking part, please contact lead author Dr Elisa Becker via elisa.becker@phc.ox.ac.uk.
Read the full paper 'The effect of increasing availability of vegetarian meals on their sales in worksite cafeterias: a stepped-wedge cluster randomised controlled trial' in International Journal of Behavioral Nutrition and Physical Activity.