If you’ve ever wondered how much of a difference your diet really makes for the planet, science may finally have an answer. A new study published in Frontiers in Nutrition found that switching from a Mediterranean-style diet to a fully vegan one can cut greenhouse gas emissions nearly in half—all while staying nutritionally balanced.
The research, led by Noelia Rodriguez-Martín, PhD, at the University of Granada, compared four different meal plans: a traditional Mediterranean diet that included meat, a pescatarian diet, a vegetarian diet with eggs and dairy, and a vegan diet made entirely from plants. Each plan delivered the same number of calories (about 2,000 a day), but the environmental outcomes were wildly different.
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“We compared diets with the same amount of calories and found that moving from a Mediterranean to a vegan diet generated 46 percent less CO2 while using 33 percent less land and seven percent less water, and also lowered other pollutants linked to global warming,” Rodriguez-Martín explained.
How going plant-based stacks up
The vegan plan was the clear winner. According to the data, the average day’s worth of vegan meals produced 2.1 kilograms of carbon emissions—compared to 3.8 kilograms from an omnivorous diet. It also used about one-third less land and slightly less water. Vegetarian diets followed closely behind, cutting emissions by around 35 percent, while pescatarian diets made smaller but still meaningful gains.
And despite old myths about nutrient deficiencies, the vegan menu met nearly all of the recommended daily nutritional requirements. Only vitamin D, iodine, and B12 needed extra attention—three nutrients that are easy to supplement or get from fortified foods.
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“Our analyses showed that all three plant-based menus were nutritionally balanced, with only vitamin D, iodine, and vitamin B12 needing a bit more attention,” said Rodriguez-Martín. “Overall, the indicators clearly highlight the environmental and health advantages of plant-based diets compared with the omnivorous baseline.”
The bigger picture
Veganism is a small but growing movement worldwide. Only about 1.1 percent of the global population currently identifies as vegan, but the numbers are climbing. In Germany, the vegan population roughly doubled between 2016 and 2020, reaching two percent. In the UK, it jumped 2.4 times between 2023 and 2025 to nearly 5 percent of the population.
That momentum tracks with public concern about both personal health and the climate. Diet-related diseases such as heart disease and diabetes continue to rise globally, while the food system remains a major driver of greenhouse gas emissions—responsible for roughly a quarter of all emissions, according to the United Nations.
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Past research backs up the new study’s findings. Harvard researchers also reported that healthy plant-based diets—rich in vegetables, grains, legumes, and fruit—had significantly lower greenhouse gas emissions and required less cropland, irrigation water, and fertilizer than meat-heavy diets. The message across all the data is consistent: eating more plants pays off in a big way.
Small steps, big impact
The takeaway from Rodriguez-Martín’s research team is refreshingly practical; gradual changes—like choosing oat milk over dairy or swapping one meat-based meal a day for a plant-based option—add up over time.
“But in our four-way comparison—omnivorous, pesco-vegetarian, ovo-lacto-vegetarian, and vegan—the pattern was clear: the more plant foods, the smaller the ecological footprint,” said Rodriguez-Martín.
“You don’t need to go fully vegan to make a difference. Even small steps toward a more plant-based diet reduce emissions and save resources. Every meal that includes more plants helps move us toward healthier people and a healthier planet,” she continued.
For anyone on the fence about eating more plant-based, the science is clear: it’s not just a personal choice—it’s a powerful climate solution that starts right on your plate.
For more plant-based stories like this, read:
Dining and Cooking