Cafeteria food swaps

Although intention is important, my experience is that many people would like to contribute more to reducing climate change but are either blocked by system barriers or balancing competing priorities. I was definitely interested therefore in a research study that investigated how combining different menu options impacted overall emissions.

Flynn and colleagues (2025) looked at the meal options in a UK university cafeteria. The cafeteria has three meal options a day for five days leading to 15 total meals. But these 15 meals could be offered in 1.4 million different combinations. The researchers conducted their study by looking at the past week’s menu options and asking students about preferences. They then adjusted the combinations so that the actual preferences of the students were more likely to choose a carbon friendlier option each day. The same process also helped reduce saturated fatty acid intake.

What were the improvements?

The cafeteria served about 5000 meals over four weeks. Through the adjustments, they reduced the carbon emissions by 30.7%. They also reduced the saturated fatty acid intake by 6.3%.

One of the really interesting aspects of this is that the students didn’t notice. This means that it was just structural changes and didn’t require any choices on the part of the students. I think this is good because we need our structures to support climate action. But, I do wonder how talking about it might help people make climate friendlier choices in other aspects of their lives.