Haven't gone vegetarian or vegan, but did cut out a large amount of meat (just have 2-3 turkey sausage links at lunch), cheese, and processed foods from my diet. Replaced eating chicken or beef for dinner with a veggie burger patty or tofu but will sometimes get a meat dish for dinner on weekends. Among some other diet changes, have already lost 16+ pounds in about four weeks so far. Feel so much better, too- and don't miss eating meat all the time.
Can't handle Beyond Burgers, though- tastes fantastic, but makes my stomach feel awful afterwards.