I have been a vegetarian for 7 years. Coincidentally, my weight has been slowly rising for about that length of time. Part of the weight gain has to do with menopausal changes, but I know the biggest part is due to my diet.
Truth be told, while I am committed to being a vegetarian, I think it was easier to maintain my weight when I wasn't. I never ate much red meat, but chicken, turkey and fish are good, lean sources of protein that are filling and easy to prepare. Too often I find myself eating carbohydrate-filled meals and snacks without enough attention to the proper mix of protein, fats and carbs, simply because carbs are so much more available. Bread, pasta, cereal, chips, pizza, packaged foods, the list goes on and on. And I have always detested eggs, which makes it even a little more difficult.
I'd love to hear from someone with insight on how they make their vegetarian diet work, easily, and perhaps even lost or are losing weight in the process!