Researchers found that re-arranging a menu can drastically influence people’s dietary choices, encouraging them to eat less meat. According to the study, doubling the number of vegetarian and vegan options on the menu reduced the number of meat orders by up to 80%. The restaurants’ overall sales of food were not affected by the extra meat-free options.

Researchers at the University of Cambridge analyzed a year’s worth of cafeteria sales data. In total, more than 94,000 meal choices were assessed from three colleges at Cambridge.

The study found that increasing the number of vegetarian options from 25% of the menu’s items to 50% lead to significantly more meat-free orders. According to the results, the number of meat orders fell by 40% to 80%, without affecting the cafeteria’s sales. What’s more, the researchers found no evidence of the so-called “rebound effect” — the idea that customers who eat less meat at lunch might compensate by eating more in the evening.

This is the first study that investigated how rearranging a menu can influence meat-free meals.

“Shifting to a more plant-based diet is one of the most effective ways of reducing the environmental footprint of food,” said study lead author Emma Garnett, a conservationist and PhD candidate from Cambridge’s Department of Zoology. 

“Replacing some meat or fish with more vegetarian options might seem obvious, but as far as we know no one had tested it before. Solutions that seem obvious don’t always work, but it would appear that this one does.”

The findings are important in today’s climate emergency context. Livestock provides only 18% of all the calories we consume, but takes up 83% of all farmland. Every pound of beef requires about 8000 liters of water, whereas an equivalent quantity of potatoes consumes over a thousand times less water. Even eggs only need about of fifth of what beef needs.

Environmental aspects aside, eating less animal protein is also better for your health, with studies showing that it increases lifespan. Most recently, the widely publicized EAT-Lancet Report, produced by an international team of health, agriculture and sustainability experts, recommended consuming less than half an ounce of red meat per day.

While going vegetarian or vegan is not for everyone, consuming less meat — say from every day to once a week — can have a huge positive impact on the environment.

“Flexitarianism is on the rise. Our results show that caterers serving more plant-based options are not just responding to but also reshaping customer demand,” Garnett said.

“Simple changes such as increasing the proportion of vegetarian options could be usefully scaled up, helping to mitigate climate change and biodiversity loss,” she said.  

More and more people are growing aware of the need for more sustainable practices in the global food supply, with millennials being the fastest to react.

Co-author Theresa Marteau, Professor of Behaviour and Health at Cambridge, said: “Education is important but generally ineffective at changing diets. Meat taxes are unpopular. Altering the range of available options is more acceptable, and offers a powerful way to influence the health and sustainability of our diets.”

And, wherever there’s a pressing problem, innovation is bound to happen. One such innovation is plant-based meat, such as the growingly popular Impossible Burger by Impossible Foods, which relies on an ingredient from genetically modified yeast to incorporate “heme,” an iron-containing molecule into the product, allowing its meats to “bleed.” While such meat-free alternatives are rather expensive today, a recent study found that they will soon become cheaper than real meat once the industry scales.