According to a new study, people who consume beef could reduce the carbon footprint of their diet by as much as 48% to gain a more sustainable diet, by swapping one serving per day for a more planet-friendly alternative.
A new Tulane University study, published in The American Journal of Clinical Nutrition, explained that achieving a sustainable diet may be simpler and more rewarding than once thought.
Using real-world data from a survey of what the American public eats in an average day, with more than 16,000 participants, researchers from Tulane University School of Public Health and Tropical Medicine and the University of Michigan calculated how much of a difference people could make if they swapped one high-impact food item for similar, more sustainable options.
Study analysis
For instance, the study states that Americans who consume beef could reduce the carbon footprint of their diet by as much as 48% by exchanging just one serving per day for a more planet-friendly alternative
They examined how the change would influence two metrics – their daily diets’ greenhouse gas emissions and water scarcity footprint, a measure of the irrigated water used to produce the foods they eat that takes into account regional variations in water scarcity.
The highest impact item discovered in an American’s diet was discovered to be beef, and around 20% of survey respondents ate at least one serving of it in a day. If they collectively swapped one serving of beef, such as choosing ground turkey instead of ground beef, the greenhouse gas emissions fell by an average of 48% and water-use impact declined by 30%.
“People can make a significant difference in their carbon footprint with very simple changes — and the easiest one would be to substitute poultry for beef,” explained lead author Diego Rose, a professor of nutrition and food security at Tulane University’s School of Public Health and Tropical Medicine.
Environmental impact of beef consumption
The study also examined how the change would affect the overall environmental impact of all food consumption in the US in a day — including the 80% of diets without any changes. If only the 20% of Americans who ate beef in a day switched it to an alternative source for one meal, that would reduce the overall carbon footprint of all US diets by 9.6% and reduce water-use impacts by 5.9%.
Agricultural production accounts for about a quarter of global greenhouse gas emissions and about 70% of global freshwater withdrawals. For the study, researchers built an extensive database of the greenhouse gas emissions and water use related to the production of foods and correlated it to a large federal survey that asked people what they ate over a 24-hour period.
Although substituting beef had the greatest impact, they also measured the impact of changing other items. Replacing a serving of shrimp with cod reduced greenhouse gas emissions by 34% and replacing dairy milk with soymilk resulted in an 8% reduction.
The greatest reduction in the water scarcity footprint came from replacing asparagus with peas, resulting in a 48% decrease. Substituting peanuts in place of almonds decreased the water scarcity footprint by 30%.
Although individual substitutions were at the foreground of the study, Rose explained that addressing climate change must involve more than singular actions.
The influence of a more sustainable diet
“The changes needed to address our climate problems are major,” concluded Rose. “They are needed across all sectors and along all levels of human organisation from international agencies to federal and state governments to communities and households. Many individuals feel strongly about this and wish to change our climate problem through direct actions that they can control. This, in turn, can change social norms about both the seriousness of the problem and the potential solutions that can address it. Our study provides evidence that even simple steps can assist in these efforts.”
