This paper’s purpose is to shed light on the current understanding of the environmental benefits of vegetarian and vegan diets, considering the inclusion of a significant share of processed foods, such as plant-based burgers. We review recent Environmental Life Cycle Assessments of the three main diet types, omnivore, vegetarian, and vegan, and then assesses the environmental impacts of adding two commercial brands of plant-based burgers to vegetarian and vegan diets. The recent literature confirms that compared to omnivore diets adhering to the same dietary guidelines, vegan diets reduce land-use impacts by 50–86%, water use by 22–70%, and greenhouse gas emissions by 21–70%, while vegetarian diets achieve reductions of 27–84% in land use, 15–69% in water use, and 24–56% in greenhouse emissions. The environmental benefits of vegan and vegetarian diets are not affected by the consumption of highly processed plant-based burgers. Consumers reduce land use, water use, and greenhouse gas emissions between 87% and 96% by choosing a Beyond or Impossible burger instead of a regular beef patty. These results are robust to the uncertainties associated with a variety of beef production systems; there is no indication that a situation or condition may make beef burgers more environmentally friendly than these two plant-based alternatives, or that the addition of plant-based meats to vegan and vegetarian diets may reduce their environmental benefits.
Characterizing Land Use Impacts on Functional Plant Diversity for Life Cycle Assessments