Environment: Impacts of nutritionally sound plant-based and meat diets analysed

By replacing meat with protein-conserving plant alternatives Americans could satisfy key nutritional requirements, while eliminating pastureland use and reducing 35-50% of the cropland currently needed for food production. These findings are reported in a modelling study in Scientific Reports, which suggests that use of nitrogen fertilizer and greenhouse gas emissions would also be reduced, while only food-related water use would rise.

Gidon Eshel and colleagues used a computer model to devise hundreds of plant-based diets to replace either beef alone or all three dominant US meat types: beef, poultry and pork. Plant-based diets consisted predominantly of soy, green pepper, squash, buckwheat and asparagus. The authors’ goal was to model a range of plant replacement diets that were at least as nutritious, if not more beneficial, than the meats they replaced, while also assessing their environmental impact. Diets were modelled to exactly match the protein content of the meat they replaced - 13 g of protein per day from beef or 30g of protein per day from all three meat types - while also satisfying 43 other nutrient requirements, such as vitamins and fatty acids.

Buckwheat and tofu jointly delivered a full third of the total protein of diets that replaced all meats, yet accounted for only 12% of the nitrogen fertilizer and water and less than 22% of the cropland needed to produce the meats they replaced. Soy contributed the most protein to beef-replacing diets, but accounted for only 6% of the overall nitrogen fertilizer needed to produce beef. Replacing meat with plant alternatives was estimated to save approximately 29 million hectares of cropland, 3 billion kg of nitrogen fertilizer, and 280 billion kg carbon dioxide per year in the US. Food-related water use was projected to rise by 15%.