People choose healthier and more sustainable dishes after menu reshuffle

By grouping popular but unhealthier and less sustainable meals on one day in a canteen menu, UK researchers have reduced the carbon footprint of diners’ weekly meal choices by a third and significantly lowered people’s saturated fat intake. Meanwhile, diner satisfaction levels were largely unaffected by the change.

The paper demonstrates how strategic menu manipulation may effectively benefit public health and the environment without drastic recipe changes. 

Led by the University of Bristol, the researchers clustered meals with a high carbon footprint and saturated fat content, like lasagna or chicken Kiev, on the same day to ensure they would compete against each other as meal options. This made healthier options like lentil chili or cauliflower curry more likely to be chosen across the week. 

“This sneaky technique could be a game-changer in many different kitchen menu settings, especially given people’s growing appetite to make healthier decisions and the increased drive to reduce carbon emissions globally,” says lead author Dr. Annika Flynn, senior research associate at the University of Bristol. 

“Improving people’s dietary habits to deliver meaningful health and environmental benefits is a meaty challenge. So the scale of benefits generated by our relatively simple intervention of weekly menu manipulation, which didn’t change the actual dishes or recipes themselves and seemed to go unnoticed, was really surprising.”

The researchers believe their findings could help improve the diets of around 42% of UK workers who report eating at a canteen, as well as children and students eating a daily meal at schools and universities. 

Sneaking in healthy meals

The research team collaborated with the University of Bristol’s catering department, which aims to introduce healthy, more sustainable food options in higher education. Using computational mathematics, the researchers determined the popularity of different meals, enabling them to swap meals across the week. 

The team tested two different optimized weekly menus in a university residence. As a baseline, the researchers used a pre-existing weekly dinner menu with 15 meals (three per day for five days). In the next week, the team used optimized menus and switched these same items around. 

By clustering popular but less healthy and sustainable options on one day, diners were more likely to choose healthier foods, like lentil chili.“In a nutshell, we rotated two weekly menus comprising three different evening meal choices each weekday. Typically, this would generate 1.4 million menu combinations, but we slashed this by around 90% to 113,400 combinations after simply stipulating one of the meal options must be vegan to cater for diverse needs by students,” explains co-author Jeff Brunstrom, professor of Experimental Psychology at the university. 

“Our optimized menu featured the same 15 dishes as the original, just reorganized on different days to boost uptake of the more sustainable, healthier options.”

Improving nutrition intake

The paper in Nature Food details that one weekly menu reduced the overall carbon footprint by 31.4% and saturated fat intake by 11.3% across around 300 diners, while the other lowered the carbon footprint by 30% and saturated fat intake by 1.4%.

The researchers also modelled the potential for other nutritional and environmental benefits from menu switches. For example, some combinations could increase fiber intake by 69.2%, lower salt intake by 14.1%, and reduce land use by 33%. 

At the same time, the study found diner satisfaction levels largely unaffected by the change. 

“Over the years, students have become increasingly interested in the environmental impact and healthiness of their meals, so they tend to be very receptive to making changes and trying new dishes,” comments co-author Alex Sim, development chef at the University of Bristol. 

“While there will always be clear favorites, like chicken Kiev and lasagna, vegan options, which generally have a smaller carbon footprint, are also proving very popular. Structuring menus to help further promote these choices is a clear win-win. We work hard to make these options flavorful and nutritious, so it’s great to see them going down so well with students.”

Future research

The researchers say the next steps include building on their findings, testing the efficacy of menu-item swaps in other canteen environments, such as schools, hospitals, and care homes, and assessing them over longer periods. 

Beyond environmental and nutritional variables, the team says it should also consider maximizing other variables, such as vegetable consumption and profit, and minimizing factors like food waste and miles. 

“If a user-friendly version of the tool can be developed and adopted widely, this could make an important contribution toward meeting population-level targets for diet and agri-food sustainability,” concludes the paper.