Replacing meat and dairy with alternatives cuts environmental impact by up to 52%, study finds

Replacing meat and dairy with alternative products could significantly reduce the environmental footprint of diets, but risks leaving key nutritional gaps if not carefully managed, according to a new peer-reviewed study published in Communications Sustainability.

• Replacing meat with alternatives reduced environmental impacts by up to 52%, with consistent reductions across greenhouse gas emissions, land use, and acidification.
• Dairy alternatives often lacked key nutrients such as calcium and iodine, while vitamin B12 remained lower across most plant-based replacement scenarios.
• Ingredient choices, including almond and coconut inputs, increased water scarcity and freshwater eutrophication impacts in some dairy-free diets.

The research, led by Eric Mehner, Alba Reguant Closa, Moritz Herrmann, Thomas Nemecek, Aline Stämpfli, Barbara Walther & Mélanie Douziech, combined environmental life cycle assessment data with detailed nutritional analysis to evaluate how replacing meat and dairy products affects both sustainability and dietary quality. The work focused on Switzerland as a case study, but the findings were considered relevant to other high-income countries with similar consumption patterns.

The results showed that substituting meat alone delivered clear environmental benefits. Across a range of modeled diets, replacing meat reduced greenhouse gas emissions, land use, and terrestrial acidification, with overall environmental impacts falling by as much as 52%. Similar reductions were observed when both meat and dairy were replaced, although the outcomes were more complex.

At the product level, most meat and dairy alternatives demonstrated lower environmental impacts than their animal-based equivalents. However, the study identified notable exceptions. Certain products, including falafel, insect-based alternatives, and several dairy substitutes, showed higher water scarcity impacts. Almond-based drinks were highlighted in particular, as they required significant water inputs despite containing relatively small amounts of almonds.

Cheese alternatives also stood out for their environmental profile. The researchers found that many of these products had elevated freshwater eutrophication impacts, largely driven by the use of coconut oil. This ingredient, commonly used to replicate the texture of cheese, was associated with higher nutrient emissions in existing environmental datasets.

While the environmental case for replacing meat appeared relatively straightforward, the nutritional picture was more nuanced. The study found that overall nutrient density scores were often similar between alternatives and their animal-based counterparts, but this masked significant variation in individual nutrients.

Vitamin B12 emerged as a key concern. Animal-based products consistently contained higher levels of B12, while most plant-based alternatives relied on fortification to provide this nutrient. Calcium and iodine were also identified as critical gaps, particularly in dairy alternatives, which frequently contained lower levels than milk and other dairy products.

At the diet level, these differences became more pronounced. When meat, dairy, and their alternatives were removed entirely, the modeled diets fell short of recommended intake levels for calcium, iodine, and vitamin B12, reaching only 36%, 59%, and 47% of reference values respectively. Replacing dairy products further reduced the intake of these nutrients, while replacing meat primarily affected vitamin B12 levels.

By contrast, other nutrients were less affected by substitution. The study found that fiber, protein, iron, and vitamins A, C, and E remained adequate across most scenarios. In some cases, alternatives even improved dietary composition, with higher levels of fiber, magnesium, iron, and vitamin E compared to animal-based products. Saturated fat intake also decreased consistently when meat and dairy were replaced.

However, the researchers emphasized that these benefits did not eliminate the need for careful dietary planning. Because the modeled diets assumed a direct one-to-one replacement of products without broader changes in eating patterns, any nutritional gaps were not compensated for by other foods.

Environmental trade-offs were also observed at the diet level. While replacing meat reduced all assessed environmental impacts, replacing dairy led to mixed outcomes. Global warming potential, land occupation, and acidification decreased, but water scarcity and freshwater eutrophication increased in some scenarios. These increases were linked to specific ingredients, particularly almonds and coconut oil.

The findings underscored the importance of ingredient selection in alternative product design. Variations in raw material sourcing and formulation led to significant differences in both environmental and nutritional performance. In some cases, environmental impacts varied by up to 60% depending on the origin of ingredients such as soy, while nutrient profiles could differ substantially between products within the same category.

Despite this variability, the study found that the act of replacing meat and dairy had a greater overall impact than the specific choice of alternative. Differences between animal products and alternatives were generally much larger than differences within alternative product groups.

The researchers highlighted that nutritional adequacy remained the main constraint on large-scale dietary shifts. While most nutrient requirements could be met without meat and dairy, the consistent shortfalls in calcium, iodine, and vitamin B12 pointed to the need for improved product formulation and fortification strategies.

They noted that vitamin B12 supplementation was already common among populations at risk of deficiency, but calcium and iodine remained broader public health concerns. Fortification practices, they suggested, would need to better reflect consumption patterns to ensure adequate intake.

The study also pointed to challenges for consumers navigating an increasingly complex food landscape. Wide variability in nutrient content between products made it difficult to make informed choices without detailed knowledge or time to compare labels. Although front-of-pack labeling systems had been introduced to simplify decision-making, none had achieved widespread adoption.

From a development perspective, the findings highlighted clear priorities for the alternative protein sector. Products needed to balance environmental performance with nutritional quality, incorporating lower-impact ingredients while ensuring adequate levels of key micronutrients. Combining different protein sources, such as cereals and legumes, was identified as one strategy to improve overall nutritional value.

The researchers acknowledged several limitations in their analysis. Cooking and preparation methods were not included, which could influence both environmental impacts and nutrient availability. Nutrient bioavailability, an important factor when comparing plant and animal foods, was also not assessed due to limited data. In addition, some alternative products, including insect- and mycoprotein-based foods, lacked comprehensive environmental datasets.

Even so, the study provided one of the most detailed assessments to date of how existing meat and dairy alternatives perform within real-world diets. By combining product-level and diet-level analysis, it offered a clearer picture of the trade-offs involved in shifting toward more sustainable eating patterns.

The authors concluded that while alternatives offered a clear pathway to reducing the environmental impact of diets, they were not inherently equivalent to the products they replaced. Achieving both sustainability and nutritional adequacy would require more targeted product development, improved fortification, and greater transparency across the food value chain.