UC Santa Barbara

The Anthropocene crisis demands rapid, radical responses to reduce human consumption and impact on the environment in order to avert catastrophic effects on humans, other organisms, and the environment. The food system is a major contributor to this crisis and an essential component of an adequate response. Here we review current research to compare the environmental impacts of healthy, sustainable, plant-based diets (HSPBDs) v. standard omnivorous diets, and their potential for mitigating the negative environmental impacts of the food system. Because plant foods overall are much more ecologically efficient than animal-sourced foods (ASFs), many fewer resources are needed to produce them, and there are smaller environmental impacts—climate warming, nitrogen and phosphorus pollution, fresh-water use, air pollution, land use, and biodiversity loss—per unit mass, protein and calories of food. This means that HSPBDs also have much smaller impacts than standard omnivorous diets, and because they are healthier, they generate less environmental impact from health-care expenses for diet-related chronic diseases. Also, production of ASFs increases the prevalence of infectious diseases in humans much more than production of plant foods. A logical extension of this cumulative evidence is that ASFs represent a form of over or superfluous consumption, compared to plant-based foods. Because the most affluent populations have the most animal-source intensive diets, and therefore the most superfluous resource consumption, a move to HSPBDs in these populations has the potential for increasing food equity by freeing production resources for under-consuming populations in our resource-limited world. While there is some disagreement about the details of differences between HSPBDs and standard omnivorous diets, the vast majority of research shows that HSPBDs have much lower environmental impacts. Awareness of these comparative impacts can be a stimulus for action to ensure that shifting to HSPBDs plays its required role as a critical component of the move from superfluous to sufficient consumption required for an effective response to the Anthropocene crisis.