Promote flexitarian diets worldwide: Supplementary information to: Governments should unite to curb meat consumption

Marco Springmann and colleagues warn that we must shift to more plant-based ‘flexitarian’ diets if we are to reduce the food system’s projected greenhouse-gas emissions and meet the targets of the 2015 Paris Agreement (Nature 562, 519–525; 2018). We urge countries to work with the United Nations towards a global agreement on food and agriculture that promotes the adoption of such diets, which are more sustainable than meat-based diets and are backed by evidence on healthy eating.

Such an agreement would be in line with findings by focus groups in the United States, China, Brazil and the United Kingdom, which indicate that governments should urgently address unsustainable meat consumption (see go.nature.com/2asd1ag). In industrial agriculture, cereals that are edible to humans are fed to animals for conversion into meat and milk. This undermines our food security: rearing livestock is efficient only if the animals convert materials we cannot consume into food we can eat. That means raising them on extensive grasslands, rotating integrated crop-livestock systems and using by-products, unavoidable food waste and crop residues as feed.

Feeding animals exclusively on such materials would greatly reduce the availability and hence the consumption of meat and dairy products, as well as the use of water, energy and pesticides — thereby cutting greenhouse-gas emissions.