Vegetarianism is a complex set of beliefs and practices, spanning from the extreme "fruitarianism," where people only eat fruits and other plant parts that can be gathered without "harming" the plant, to various forms of "flexitaranism," like pollotarianism (poultry is okay to eat) and pescetarianism (fish okay). So, what does science have to say about this? What is the ethical case for vegetarianism? And, is it true that vegetarians are more intelligent than omnivores? Not unexpectedly, the answers are complex, so the debate will rage on.