Sandwiches Are Bad for the Environment, and Bacon, Egg and Sausage Are Worst of All

Fresh-made daily sandwiches on display at Amazon Go on January 22 in Seattle, Washington. Sandwiches have a previously unrecognized impact on the environment. Stephen Brashear/Getty Images

Sad news about sandwiches today.

Researchers in the U.K. calculated how much they are contributing to climate change. They found that the 11.5 billion sandwiches eaten each year in that country produce the same greenhouse gas emissions as 8.6 million cars. Alas, the hero is no hero for the environment.

A cafe worker prepares sandwiches during lunch hour at a cafe in central Sydney on September 10, 2009. Reuters/Tim Wimborne

Researchers from the University of Manchester considered 40 combinations of sandwiches. They scrutinized several factors, including homemade versus pre-packaged, production of the ingredients, the actual ingredients and how much food was wasted in making it.

The bread-encased meal with the worst impact on the environment was the all-day breakfast sandwich, which has egg, bacon and sausage. Just one of those sandwiches produces carbon dioxide emissions equivalent to 12 miles of driving. The sandwich with the lowest impact was a homemade ham and cheese sandwich. The findings will be published in the July volume of Sustainable Production and Consumption.

Considering the love of sandwiches by U.K. citizens—a trait that may echo the feelings of many on this side of the pond—researchers say that understanding their greenhouse gas emissions is important, especially considering those emissions are the primary cause of climate change.

"Given that sandwiches are a staple of the British diet as well as their significant market share in the food sector, it is important to understand the contribution from this sector to the emissions of greenhouse gases," Adisa Azapagic, co-author of the study and sustainable chemical engineering professor at the University of Manchester, said in a statement.

The study further revealed that agricultural production and processing of the ingredients were the highest contributors to the carbon footprint of sandwiches, though it depends on the type of sandwich. For ready-made sandwiches, agricultural production and processing accounted for 37 to 67 percent of greenhouse gas emissions. Keeping a sandwich cool at a supermarket or deli also increases the polluting impact, accounting for up to 25 percent of its emissions. Packaging accounts for 8.5 percent and transportation and further refrigeration accounts for 4 percent.

But knowing sandwich enthusiasts may be hard-pressed to stay away, even with these stark numbers, the researchers came up with some solutions to curb the climate impact. Azapagic suggested changing food labels to increase the use-by date, which "are usually quite conservative," she said. That extension would reduce food waste by over 4 million pounds, researchers say.

And ingredients that have a high carbon footprint, such as lettuce, tomato, cheese and meat, could also be reduced or omitted entirely. Reducing meat and cheese would be healthier, too, the researchers noted. That echoes another recent study, which found that eating healthier was better for the environment. In other words, a bread and condiment sandwich is probably the way to go.

If you can't bear parting ways with your favorite hoagie, there's another solution the study found: Making your sandwich at home rather than eating a pre-made one could cut carbon emissions by half. Go on, let the hero of this story be you.