A plant based diet only requires around one quarter of the land and water needed to produce a typical Western diet. Farm raised animals consume much more resources, water, and calories than they produce. This  means far greater quantities of crops and water are needed to produce animal products needed to feed humans, than are needed to feed people on a direct plant-based diet. With water and land becoming scarcer globally, world hunger increasing and the planet's population rising, it is much more sustainable to eat a plant based diet than use up precious resources feeding the farmed animals