Researchers at the Stanford School of Medicine have identified a set of simple food swaps that can make a big difference in an individual’s carbon footprint — without the need for a drastic dietary overhaul.
The suggestions include exchanges as easy as replacing beef with chicken in a burrito or selecting plant-based milk over dairy. If universally adopted, such choices would lower the U.S. dietary carbon footprint by more than 35%, the researchers found.
“Many people are concerned about climate change, but sweeping dietary change can be hard,” says the study’s lead author. “Instead, we’ve identified simple, achievable substitutions — small changes — that can still produce a meaningful impact.”
The researchers also assessed the health impacts of their suggested changes using the U.S. Department of Agriculture’s Healthy Eating Index — which measures how healthy our diets are — and found that the changes stood to improve overall dietary quality.
About the study
To identify easy food substitutions that could have an outsized climate impact, the researchers merged data on food-related greenhouse gas emissions with a large, nationally representative survey on what people eat in the United States.
In each of four food groups — protein, mixed dishes, dairy and beverages — they identified foods that disproportionately contribute to greenhouse gas emissions.
They then matched each of these foods to a similar option with a much lower carbon footprint to propose a swap and calculated what the impact would be both for an individual’s carbon footprint and for the country’s if the changes were made.
The key was to find food swaps that were culinarily equivalent so that it would be easy for people to adopt the new dishes.
The beef triple whammy
Substitutions in the categories of protein and mixed dishes stood to make the biggest impact, with a shift away from beef leading the way in both cases.
Choosing ground beef for a hamburger, for example, means your patty will have a carbon footprint that’s 8 to 10 times higher than a chicken patty and around 20 times higher than a vegetarian patty.
On average, choosing chicken for a meal instead of beef reduces the greenhouse gas emissions needed to make the meal by an amount roughly equivalent to driving 9 miles in a car.
This might not seem like a lot on an individual level, but if everyone participated in these swaps it could have a substantial impact in the nation’s dietary carbon footprint — potentially reducing emissions by the equivalent of hundreds of millions of passenger vehicle miles each day.
Beef is particularly problematic for the environment for three reasons. First, cows produce high quantities of methane, a potent greenhouse gas, simply by digesting their food. Second, cows require a significant amount of land for grazing, driving clear-cutting of forests in many parts of the world. Finally, cows have a much longer life cycle than poultry and other, smaller animals, which means their own lifelong dietary footprint is much larger by the time they can be used for food.
Beef was just one of many swaps the team identified in a list that has something for everyone. Salmon is better than crab, for example, and pork is better than lamb (though chicken is better than pork).
But the team wants to focus on encouraging consumers to opt out of the foods they most commonly eat that have the heaviest carbon footprint, as those have the biggest impact nationwide.
The researchers are already studying what kinds of educational campaigns can encourage people to make swaps with three major targets in mind: replacing beef and pork with chicken or vegetarian entrees, replacing cow’s milk with non-dairy milk, and replacing juice with whole fruit. (Juice has a much higher carbon footprint than whole fruit as it requires much more fruit to be squeezed and tossed to create an equivalent serving.)
Source: Nature Food, October 26, 2023
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