Your Sad Desk Lunch Is Actually Bad For The Planet, According To This Study

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Sandwiches are the best thing since, well, sliced bread. But a groundbreaking new study from British scientists has broken down, for the first time, exactly which sandwiches are worst for the planet, and which might be best for reducing your carbon footprint — and while supermarket and ready-made sandwiches definitely are the worst for environmental impact, ready-made lunches aren't necessarily that great either. Be prepared to feel a bit awkward about your lunch al desko.

Measuring carbon footprints is an interesting exercise. For the study, just published in Sustainable Production and Consumption, the scientists behind the sandwich-judging looked at many areas of environmental impact, from the obvious (plastic packaging and the transporting of ingredients in pollution-producing trucks) to the not-so-obvious (agriculturally intensive ingredients and how long the finished products were refrigerated for). They looked at 40 different sandwich "types" with many different variables, from the types of ingredients to how the sandwich-makers managed waste, and came up with an image of the humble lunchtime sandwich that's less benign than you might think.

The obvious factor, being made commercially rather than at home, does in fact have a big impact. The scientists found that home-packed sandwiches can reduce the carbon emissions of your lunch by half compared to store-bought varieties. However, many other factors come into play, too. Ingredients many of us love on our lunchtime sandwiches, including pork products, cheese, lettuce and tomato, actually have high agricultural costs. The highest possible carbon imprint was found in a bacon, sausage and egg sandwich from a store, but popular home-made varieties of ham and cheese, while they have smaller footprints comparatively, are still relatively un-green. A store-made egg and cress sandwich can generate a footprint of 739g of CO2 eq., a measurement of environmental impact that expresses the amount of damage a collection of different greenhouse gases produces by estimating the equivalent amount of harm in carbon dioxide. A home-made ham and cheese option, however, can have a footprint of up to 843g CO2 eq. per sandwich.

In a press release, the sandwich scientists announced that the U.K.'s habit of eating 11.5 billion sandwiches "generates, on average, 9.5 million tons of CO2 eq., equivalent to the annual use of 8.6 million cars." It's an odd way to think of your lunch choices, but it's a necessary one. And ingredients may be the most important part of the puzzle; while packaging and refrigerating sandwiches influence around 13 percent of their greenhouse gas emissions, how the filling is grown and processed can determine over 65 percent of its environmental cost.

Environmentally friendly perspectives on food have been gaining ground for years. Farm-to-table restaurants and eating that emphasizes the use of waste and the reduction of food processing are in vogue; many of the restaurants currently in the world's top 50 ranking highlight environmentally friendly eating, seasonal ingredients, and low-impact business models. From entire restaurants serving 'waste' fruit and vegetables to on-site farms and herb gardens that reduce the cost of transporting ingredients to zero, the haute cuisine industry is going green. But even the most artisanal, green-credentialed sandwich-makers may be causing more problems than they anticipate. Wheat, dairy, meat and some vegetables all have environmental costs that increase depending on how and where they're prepared. That means that even vegan-friendly sandwiches have costs.

Realistically, all human food will create an environmental cost, but the sandwich may be causing more damage than everyday lunchers had anticipated. The best option, according to the scientists? Make your own at home, don't use pork products or cheese, and try to focus on locally-grown veggies and things you got out of your own garden. And if you must eat out, try to pick varieties with low-impact packaging that haven't been languishing in a fridge for two days. The earth will thank you.