Student canteens can cut meat consumption by 80 per cent by offering more veggie dishes alongside their meat menu.
Cambridge University added more meat-free options to cafeteria menus in the hope of stopping climate change and were surprised by the result.
Their dining experiment results come after the world-famous university dropped the sale of beef and lamb on campus.
Students offered two vegetable based meals instead of just one out of four chose to eat between 40% and 80% less meat – the biggest food contributor to greenhouse gas emissions.
Scientists from the University of Cambridge’s departments of Zoology, Geography and Public Health gathered over a year’s worth of mealtime sales data – 94,000 meals – from three Cambridge college cafeterias.
Two provided data on days with different menu set-ups, and a third college helped the researchers with the so-called “choice architecture” experiment which brought in more veggie options.
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.
“Universities are increasingly at the forefront of providing plant-based options that are affordable and delicious, making it easier to choose a more sustainable diet. I think that’s what really has to change.
“We’re not saying all cafeterias and restaurants should turn vegan overnight. But if food were the film industry, vegetarian and vegan meals need to land more starring roles, and meat dishes have got to stop hogging the limelight.”
The research team found the biggest jump in plant-based dining among the most carnivorous customers who picked meat or fish before more veg-based meals were added to the menu.
There was also no “rebound effect” where diners went meat-heavy on dinner after eating a vegetarian lunch.
The findings have been published in the Proceedings of the National Academy of Sciences.
Diets full of meat are leading drivers of species loss and climate change, say scientists.
Meat, fish, dairy, and egg production are responsible for some 58% of the greenhouse gas created by global food, and take up 83% of farmland despite accounting for just 18% of the world’s calorie intake.
Dr Emma Garnett, a conservationist from Cambridge’s Department of Zoology, said: “Shifting to a more plant-based diet is one of the most effective ways of reducing the environmental footprint of food.
“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.”
Dr Garnett argues that vegetarian options have been an “afterthought” on menus for too long.
She added: “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.
“Simple changes such as increasing the proportion of vegetarian options could be usefully scaled up, helping to mitigate climate change and biodiversity loss.”