When comparing a lacto-ovo vegetarian diet with a meat based diet, it becomes clear that vegetarian diets are more sustainable. In fact, if everyone in the U.S decided to be a vegetarian, it would be equivalent to 46 million cars being taken off the road (Reducing your footprint, 2011). In order to do an accurate comparison, researchers David and Marcia Pimentel conducted a study where the calorie count of meat-based and plant-based diets were matched. Factors such as the amount of feed grains used in order to produce animal products such as milk and eggs (products which are part of the lacto-ovo diet), and feed grains used to feed livestock were taken into account. This included data on the fossil fuel inputs needed for grains, vegetables, and livestock production systems. Land resources needed and water resources were also taken into account when calculating comparable sustainability (Pimental, 2003).

Results show both diets require a significant amount of nonrenewable fossil fuels, making both non sustainable in terms of green house gas emissions. The meat based diet does however require more land, energy, and water resources than the lacto-ovo vegetarian diet, making vegetarianism less sustainable in these environmental domains (Pimental, 2003).

It is important to note that American consumption of meat was used in the data. Below shows the amount of meat consumed compared to other developed countries.

By using data from the American population in the David and Marcia Pimentel study, it is no wonder that meat-based diets are so unsustainable. It may be argued that any type of excessive consumption can lead to serious environmental concerns.