Google on "Meatless Monday", it is an international effort to get people to eat meatless for one day a week ( Monday ) to reduce pollution and other environmental problems. For example, for one day a week have cereal for breakfast, A PB & J and Banana sandwich for lunch and a plate of pasta for dinner.
I've seen various articles that doing ONLY Meatless Monday helps the environment more than being a pretentious "locavore" all week long.
If you are interested in more information about the connection between good choices and the environment here are some short articles:
Successful and fortunate crime is called virtue. - Seneca