Some who eat vegan do this to consume only what they need to remove themselves from the wasteful and mean consumer culture they grew up in. Reducing their own demands could help the environment recover from abuse. Some do it because a vegan diet is more sustainable, which saves resources for others who need it. They are being altruistic. Some feel healthier and more energetic when their diet is vegan. Some have sympathy for their fellow creatures so they refuse to eat or exploit them. Even if the animal sentience is doubted, they think it’s better to err by hurting others less. * For some, the basic law against eating one’s own kind applies not only to other humans, but to other mammals, other vertebrates, or other sentient creatures. * Some believe it’s wrong to eat or use any product that comes from an animal, such as honey and leather. * Almost no vegans abjure eating yeasts or other single-cell forms of life, and most feel fine after drinking beer.