Feeding 7.5 billion people around the world is no easy task. Some 570 million farms – each with their own strategies in land use, packaging, transportation, size, and products – take on the task of fulfilling an array of dietary needs. But which diet has the least impact on our planet?

Scientists say if you want to save the planet, go vegan.

“A vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gases, but global acidification, eutrophication, land use and water use,” lead researcher Joseph Poore of the University of Oxford, UK, told The Guardian.

In order to determine the impact of our agriculture, researchers at Oxford compiled a robust dataset of how our diets are taking a toll on the planet by analyzing nearly 40,000 farms in more than 100 countries that produce 90 percent of food that is eaten in the world. From farm to table, they looked at how these different products stack up in terms of greenhouse gas emissions (GHG), land and water use, ocean acidification, and water pollution.

According to data published in Science, avoiding meat and dairy is the single best way to reduce your environmental impact.

Without meat and dairy consumption, global farmland could be reduced by more than 75 percent and still feed the world. Even the impact of the most sustainable animal products far exceed those of vegetables and produce. For example, livestock provides 18 percent of calories and 37 percent of protein consumed globally, but take up 83 percent of farmland while producing 60 percent of greenhouse gas emissions from agriculture.

It’s not just the type of food being produced and consumed, but where and how it’s done. Beef cattle raised on deforested land creates 12 times more greenhouse gases and uses 50 times more land than grazing in a more suitable pasture – the impact can vary 50-fold just within the same product. Once thought to be a sustainable alternative, freshwater fish farming is also proving to be detrimental to the environment. Waste and unconsumed food drop to the bottom of fish ponds, making it the “perfect environment for methane production.”

There is no one-size-fits-all solution, either. Poore says identifying ways to reduce our impact will come in many forms. Starting at the top, he believes policymakers should incentivize producers who meet environmental targets and establish sustainable practices in suitable environments. These producers then need to monitor their impact on the environment and communicate it to consumers, who can then make informed decisions about their diet.