It can be confusing to determine whether foods are truly “sustainable,” “green,” or “eco-friendly,” and these terms can occasionally be simply misleading. When everything from meat to beer is now sold with a “carbon neutral” label, how can you know that the stuff you’re eating is indeed sustainable?

There is compelling evidence that plant-based diets use less energy and produce fewer pollutants than diets high in animal products. But what if those plant-based foods had to fly halfway around the world to get to your table? And how much do different cooking methods impact carbon emissions, either positively or negatively? A British public service broadcaster undertook a two-week experiment with independent sustainability researcher Rebecca Lait and Sarah Bridle, a professor of food, climate, and society at the University of York in the UK, to find out the answers.

In the end, it seems that not all vegans have the smallest carbon footprints; it all depends on what you eat. A plant-based diet generally results in significantly lower emissions, as the study has shown. Eating a lot of meat, especially beef, is bad for you and will surely cause emissions to rise significantly. It also revealed some of the most thoroughly studied techniques for minimizing the impact of food on the environment.