A vegetarian diet plan is a great choice simply because it's vegetarian. Has anyone ever heard of an unhealthy vegetable? One of the great things about a vegetarian diet plan is that you can stay full and not worry about the calories. Just limit the starchy vegetables like potatoes, and eat all the green leafy vegetables you can handle. One thing you want to make sure of is to get some protein with your a vegetarian diet plan, so include some beans or lentils. Eat your way into a slimmer you with a a vegetarian diet plan.