Of course you can get pizza and pasta in Rome without meat, but the best meal we had in Rome was at restaurant called Un Punto Macrobiotico. It was in the neighborhood closeby to the apartment where we were staying. I can't explain the difference between vegan, vegetarian and macrobiotic but I know good plentiful food when it's put in front of me.
For 8 euros, we were given soup followed by full plates with 4 different vegetarian dishes. I think bottled water was included. We were stuffed by the time we cleaned the plates. Then they came by and offered us seconds!!!!!! It was included in the price.
In the last 4 years, we have moved to a diet much more vegetable and fruit centric, with meat appearing on the table an average of 2-3 days a week. Since moving to FL, I do eat more fish, but we've maintained a good diet and are healthier and lighter than ever before and I owe it all to this place showing us just how much variety and flavor vegetarian cooking could provide.