Back maybe 8 years ago I was a vegetarian on South Beach. The first phase is pretty low carb, similar to Atkins. I remember eating a lot of soup, stuffed vegetables (mushroom caps, peppers, zucchini), tofu, quorn, veggie burgers, eggs, nuts, cheese, and salad.
I don't really recall if I altered the plan to add more carbs for counting or if I just stayed away from very starchy vegetables, fruits, and any grains.
It wasn't very easy, but I was also in my early twenties and worked entirely too many hours. It would probably be much more manageable now.