What about plants?
There is currently no reason to believe that plants experience pain, devoid as they are of central nervous systems, nerve endings, and brains. It is theorized that the main reason animals have the ability to experience pain is that it serves as a form of self-protection. If you touch something that hurts and could possibly injure you, you will learn from the pain it produces to leave it alone in the future. Since plants cannot locomote and do not have the need to learn to avoid certain things, this sensation would be superfluous. If one is concerned about the impact of vegetable agriculture on the environment, a vegetarian diet is still preferable to a meat-based one, since the vast majority of grains and legumes raised today are used as feed for cattle. By eating vegetables directly, rather than eating animals such as cows, who must consume up to 13 pounds of vegetation in order to convert them into 1 pound of flesh, one is saving many more plants’ lives (and destroying less land).