Time to ditch the steak - New study reveals dishes with significant environmental impact

What you eat impacts the planet more than you think. There are dishes that have an especially large biodiversity footprint, or impact on biodiversity. 

What dishes are the worst for the planet? Brazilian steak and Indian kidney bean curry are among those with large biodiversity footprint, according to a study published in the open-access journal PLOS ONE by scientists from the National University of Singapore. 

Food choices can have significant environmental impacts. Previous research has begun to collect files that identify the influence of specific crops on mammals, birds and amphibians. Cheng and colleagues used this data to estimate how 151 different popular dishes from around the world impact biodiversity.

The authors used lists of popular dishes taken from two popular websites standardising each dish to be 825 kCal. They calculated the biodiversity footprint of each dish's ingredient by looking at the richness, conservation status, and range of wild mammals, birds, and amphibians within the agricultural land used for the specific product, and added each ingredient's footprint together to generate an overall biodiversity footprint for every dish. Footprint scores shifted depending on whether the ingredient was locally or globally sourced, and industrially or small-scale farmed. 

The top twenty dishes with the largest biodiversity footprints included:

• meat dishes with beef and chicken: Brazilian steak dishes (picanha, churrasco, fraldinha), salsa verde pork and yukgaejang (a Korean spicy beef and vegetable stew), caldo de pollo (chicken soup)
• vegan dishes made with legumes and rice: dal (lentil soup), rajma (a kidney bean curry), chana masala (chickpea curry) and idli (a fermented savory rice cake). 

Brazilian beef and lamb dishes also had high biodiversity impacts due to the conversion of Amazon rainforest and other diverse ecosystems to pasture. For vegan and vegetarian dishes of the Indian subcontinent, rice and legumes grown industrially tended to have especially high impacts on threatened species and range biodiversity indicators. 

The twenty dishes with the smallest biodiversity footprints tended to be vegetarian and vegan dishes, that featured starchy food, grains or potatoes like French recipe  pommes frites, chips, German potato pancakes, and breads, for instance.

The authors note they didn't differentiate between wildlife able to survive in cultivated habitats, versus wildlife with specific natural habitat requirements—and looked specifically at mammals, birds, and amphibians. They also note the dishes examined here are not necessarily representative and focus on dishes from countries with a high GDP, and that recipe variation might lead to different results. Regardless, this study underscores the importance of specific ingredients and areas of production in terms of biodiversity impact.

The authors commented: "Small changes in the dish we choose to eat and where we get the ingredients from can go a long way in preventing species extinctions. In addition to the large footprint of beef and lamb dishes from countries containing biodiversity hotspots, vegetarian dishes from highly biodiverse and under strong human pressure countries like India, can be also very detrimental for biodiversity."