Plant-based diets tend to have a lower environmental impact, requiring less energy to produce their sources of sustenance, reduces water use by approximately 90%, while significantly reducing methane gas that is associated with animal protein farming. For example, cows emit a significant amount of methane gas. Statistics vary in regards to the amount the average dairy cow expels. Estimates range from 100 liters to 200 liters a day (or about 26 gallons to about 53 gallons), up to 500 liters (about 132 gallons) a day. In any case, that’s a lot of methane, an amount comparable to the pollution produced by a car in a day!