Determining if food is actually “sustainable,” “green,” or “eco-friendly” can be difficult, and these terms occasionally tend only to mislead. How can you tell if the food you’re eating is truly sustainable when everything is now sold with a “carbon neutral” label, from beef to beer?

There is strong evidence that diets high in plant goods are less energy- and pollution-intensive than diets high in animal products. What if those plant-based foods had to travel 15,000 miles to reach your table? How much of a positive or negative influence do various cooking techniques have on carbon emissions? To find out, a British public service broadcaster conducted a two-week experiment with Sarah Bridle, a professor of food, climate, and society at the University of York in the UK, and Rebecca Lait, an independent sustainability researcher.

It turns out that depending on what you consume, not all vegans have the lowest carbon footprints. According to the study, a plant-based diet typically leads to noticeably fewer emissions. Eating a lot of meat, especially beef, is unhealthy and will definitely result in a major increase in emissions. It also disclosed some of the most extensively researched methods for reducing the environmental impact of food.