Scientists assessed the environmental impact of more than 57,000 food products in the grocery store.
If consumers knew what they learned, it could lead to a more sustainable food system and improve our health.
“The goal is to have an easier and more accurately quantified way to inform consumers about the tens of thousands of different products they can purchase at grocery store” says ecologist David Tillman, a professor in the School of Environmental Sciences and Management at the University of California, Santa Barbara and co-author of the study in Proceedings of the National Academy of Sciences.
According to the researchers’ assessment, beef and lamb cause the most damage to the environment, with the impact far exceeding that of other proteins such as chicken, fish, seafood and nuts, which are also at the top of the environmental impact scale. .
“Many people believe beef taste good, and I can see why, but it’s a very inefficient way to create food for people,” Tillman says. Meanwhile, processed drinks such as soda and energy drinks were rated as having the lowest level of exposure among the food products assessed, sharing a spot with plant-based foods such as rice and tortillas.
The life cycle of nutrition
While much research has been done on the environmental impact of food items such as fruit, wheat, and beef, most foods contain many different ingredients, each of which has taken its own path to become part of a whole.
This life-cycle data, which informs the total environmental impact of the production, collection, transport and processing of the named ingredients, is largely invisible to the consumer, as are the proportions of the ingredients.
According to the study, this information gap exists because “the exact amount of each ingredient and their supply chain in each food product is often considered a trade secret.” The sheer number and variety of food products makes evaluation a “difficult” task for food companies and retailers seeking to reduce their carbon footprint.
To overcome these limitations, researchers led by first author Michael Clarke of the University of Oxford used prior knowledge from ingredient lists to infer the composition of each ingredient. They then combined this information with environmental databases to estimate impacts across four metrics: greenhouse gas emissions, land use, water stressand eutrophication potential (the amount of excess nutrients from production that can pollute the environment and waterways).
“This is the culmination of a decade since Mike and I started working on this,” says Tillman, a former adviser to Clark. “It started with us doing some life cycles and then using many of those life cycles that were published. And then we started to critically assess the quality of life cycle data available for each of the major food commodities.”
They consulted previously published papers, carried out further analysis and applied their approach to 57,000 food products found in Tesco supermarkets, a major grocery chain in the UK and Ireland.
“You walk into a grocery store in Europe, and it’s not that different from a grocery store in the United States,” Tillman says. While people around the world don’t have the same taste preferences, he adds, we tend to have similar tastes, which results in more or less the same food products in our stores.
These tastes tend to gravitate toward foods that contain high sugar levels. It’s a commodity that’s both cheap and mass-produced, with effects that have led to increased rates of obesity, diabetes and other diseases linked to overconsumption of highly processed foods that often contain high-fructose corn syrup.
“That’s what happened with the Green Revolution,” Tillman says of the unintended consequences of the world’s move in the 1950s and ’60s to high-yield industrial agricultural processes involving pesticides, fertilizers and monocultures.
“Sugar is cheap. Fats are cheap, salt is cheap. People love salty, fatty and sweet types of food; here are our taste preferences. They made perfect sense during our evolutionary past, and now that these foods are so cheap and readily available, we eat them in excess.”
Healthy for people, healthy for the environment
In a previous study, Tillman and Clark found that, overall, diets that included healthy, less processed foods were also healthier for environment.
“We know there’s a relationship here, and we wanted to apply that to individual products,” Tillman says. As a result, the researchers’ current study also ranks grocery products by dietary exposure, with plant-based foods less processed foods on the healthier end of the scale for both people and the environment, and highly processed grains and dairy toward the less healthy end.
“The healthiest diets we know are variations of the classic Mediterranean diet, which includes lots of fruits and vegetables a day, as well as whole grains,” Tillman says. “Whole grains have the advantage of containing fiber, which helps slow down the rate at which starch is converted to sugar.”
The main meat is fish, he adds, and other meats are used as flavorings and on special occasions. Other environmentally friendly and nutritious diets include vegetarian and pescatarian diets, provided that hydrogenated fats and sugars are kept to a minimum. There isn’t enough scientific evidence yet to place a vegan diet in the same group, but Tillman suspects it belongs there, too.
However, more work needs to be done to refine the researchers’ assessment. The proportion and type of ingredients in similar foods sold in grocery stores varies widely, which can lead to differences in health and environmental impacts, and there are alternative processes to consider, Tillman says.
But the hope is that this information will become widely available, enabling people to become better food choices for the health of both their bodies and the environment.
“I hope this information ends up on the packages,” Tillman says. “And I hope that it is on the packaging that the companies that make the various products will be willing to tell us the exact ingredients and their quantities so that we can give the most rigorous and honest assessment of their products.”
Source: UC Santa Barbara