The wonderful meals you can enjoy in Italy might not be around forever. Between globalization, a farming crisis, and the demand (particularly by tourists) for out-of-season products, the way Italy makes and consumes its food is changing. Just check out the relatively-sudden prevalence of grocery stores (there are three within a 5 minutes' walk from me) or the crowds that pack the (yes, few and far between, but still existing) McDonald's in Rome for proof.
The same way you'd think twice before tossing garbage into the street, think about how your choices of restaurants and foods might impact the (culinary and natural) environment around you. Katie Parla gives some excellent tips for how to be a conscientious eater — in Italy, or anywhere.