In November 2019, more than 11,000 scientists from 150 countries clearly and unequivocally declared that our planet is facing a climate emergency. The glaciers are melting, oceans are getting hotter and more acidic, sea levels are rising, and we’re experiencing greater numbers of extreme weather events. Fossil fuel use has been going up, but so has per capita meat consumption. Does what we eat play in role in climate change? Which diet has the least impact on the environment?

A plant-based diet may not only be optimal for our personal health, but for the health of our planet, too. The least healthy foods tend to cause the worst environmental impact, while the foods with the most nutrition just so happen to be the foods that cause the lowest greenhouse gas emissions.

Indeed, a systematic review found that eating a completely plant-based diet may be the optimal diet for the environment. Diets that include meat require about 3 times more water, 13 times more fertilizer, more than twice the energy, and 40 percent more pesticides than those that don’t. Looking at the total environmental impact of omnivorous versus vegetarian versus vegan diets—that is, looking not only at global warming, but also ocean acidification, agricultural run-off, smog, ecotoxicity of the water and soil, and direct human toxicity of the air we breathe, the water we drink, and the soil in which we grow our food—eating eggs and dairy may be 9 times worse than plants, and eating eggs, dairy, and meat may be 17 times worse than sticking to plant foods.

Unhealthy diets cause more death and disease than smoking, more than unsafe sex, and more than alcohol, drug, and tobacco use combined. We can address both human health and climate crises at the same time by increasing consumption of whole plant foods and substantially reducing our consumption of meat, eggs, and dairy.

The information on this page has been compiled from Dr. Greger’s research. Sources for each video listed can be found by going to the video’s page and clicking on the Sources Cited tab. References may also be found at the back of his books.

Image Credit: cocoparisenne. This image has been modified.