Reducing meat consumption is one of the most powerful levers to bring down greenhouse gas emissions: this is now widely acknowledged. But something that gets less attention is how eating less meat could also improve water quality.
A new study presents the case, showing that replacing just 10% of meat with alternative proteins in the United States could have a large potential impact on groundwater—a major source of drinking water in the country—reducing the risk of water pollution there by up to 20%.
Although agricultural groundwater pollution is a global problem, the U.S. was a good starting point for the research, as the global leader in annual meat consumption. Livestock require large amounts of feed, which itself requires significant inputs of nitrogen fertilizers to grow—one third of which is lost to the environment each year in the U.S. The result is that half of groundwater from the main aquifers sampled in the country contain nitrate concentrations above natural levels.
Increasing meat consumption therefore doesn’t bode well for the long-term health of these reservoirs and the people who rely on them. The question is whether meat alternatives would be much better, considering that they all require agricultural inputs, too.
To investigate, the researchers considered beef, poultry, and pork, and compared these to three protein alternatives: plant-based protein, insect-based protein, and cultured meat. Looking at the period between 1985 and 2020, they assessed the impact of conventional meat production methods on groundwater quality, and then used a model to simulate the potential changes that would result from a switch to the protein alternatives in each case.
Firstly, their study showed that the growth of agriculture, and livestock in particular, has consistently increased groundwater nitrate exceedance—the point at which nitrates pass the designated safe limit for environmental and human health—over the last 60 years in the U.S.
The next clearest trend the researchers picked up on through their modeling analysis, is that beef is the most resource intensive across the board—consuming more fertilizer, water, land, and producing more greenhouse gases than any other variety of meat or meat-alternative. It was followed by poultry and pork.
However, the meat alternatives aren’t footprint-free. Many plant-based meat alternatives are made from soybeans, which of course require fertilizers to grow. Insect protein farms, too, are often supplied with a diet of crops to sustain them. Even cultured meat that’s produced in a lab depends on corn and soybean feedstocks: on average, a kilo of cultured meat requires 5.6 kg of corn and 0.03 kg of soybean to sustain it, the study says.
And yet, despite the associated fertilizer use, meat alternatives still had a significantly lower groundwater impact. Per unit of protein generated, plant-based alternatives in particular stood out: “By directly consuming plant protein rather than raising animals for feedstock conversion, plant-based meat consumes fewer soybeans, which requires minimal fertilizer”—26.4 grams of fertilizer per kilo, compared to beef’s 519.5 g, the researchers explain in their work.
This translated to significantly lower groundwater impacts in the simulation. Calculating across the three alternatives, switching just 10% of meat consumption in the U.S. to plant protein, insect protein, or cultured meat, would reduce fertilizer use by 3.4%. That’s enough to cut the risk of nitrate excess in groundwater by 20%. That would reduce the number of groundwater sites currently registering unhealthily high levels of nitrates by up to 16%.
This depolluting effect could be much greater if the U.S. ate even less meat and more alterative protein. For instance, substituting 50% of meat with alternatives holds the greatest potential for reducing nitrate pollution, the researchers found. But at these higher rates, there were trade-offs that revealed some nuances of the American agricultural landscape.
For instance, in regions of the country where corn and soybeans are intensively farmed, a dramatic national increase in the consumption of alternative proteins could trigger to an expansion of crop production that leads to more fertilizer being dumped into the soil and infiltrating groundwater. So the solution may not be as simple as blanket-switching to alternative proteins.
The researchers also note that the groundwater benefits of eating less meat also depend to some degree on precipitation levels, and how much water regularly infiltrates the deeper layers of the soil. In drier regions, for example, their proposed dietary switch would have measurably more success at keeping nitrogen out of groundwater.
With these nuances in mind, the researchers settled on 10% substitution as a starting point—an amount small enough to be feasible, which could still deliver significant benefits to water quality, human, and ecological health.
Zheng et. al. “Changes in meat consumption can improve groundwater quality.” Nature Food. 2025.
Image: ©Anthropocene Magazine / Ai-generated
