You can take care of your body as a vegetarian/vegan; however, you need to be vigilant in eating the combination foods and eating enough food daily so your body gets the protein, and nutrients it needs. As a vegetarian you should be getting all your vitamins and minerals from the foods you ate except Vitamin B12 and maybe Calcium (if you have a history of bone disease in your family). Vitamin B12 supplementation you need to take because it comes from meat sources and it not available through vegetarian diet. Calcium supplementation may be needed if your intake is on the lower side depending on what you eat and your bone density. Soy products are a good source of calcium. Eat non-meat sources (soy products, nuts), vegetarian combinations (rice & beans, pasta & beans, soy cheese & pasta, salads with nuts & seeds), substitute dairy products (soy milk/soy yogurt), use plant oils, non trans-fat margarines, and eat a lot of fruits and vegetables. Eat daily high fiber breads and cereals (oatmeal). Recommend you read up on vegetarian and combinations of starches / vegetables and beans / nuts for protein, calcium, and other nutrients. Good sources of information are the American Dietetic Association website, www.eatright.org and Vegetarian Resource Group website, www.vrg.org. As a vegan you can lose weight, however, you need to have the right combos as stated above. If you choice to eat dairy products, choose low fat so you are not consuming extra fat and can lose weight. Hoped this helped you.
I started as a vegetarian. Its a great diet and all but sooo many things are still vegetarian that are very bad for you. To me losing weight on the vegetarian diet is easy if you have the right mind set and your willing to change! first off I call this the quarter, quarter, half rule. this means when you eat make half the plate greens(any), a quarter a carb(potato, corn, etc), and then the last quarter a protein. I in no way would recommend anything like soy products for various reasons. Some examples of veggie protein are beans(13.4g), seitan(21g), or you could buy a veggie supplement/protein drink. So pretty much go towards more plant based for the first phase. Once you've lost at least 50% or most of the weight you needed to loose you can add in that *little* vegetarian cheat now and then. 1-2 times a week or so. You'll actually notice if you are eating mostly greens on your plate you wont even crave or want junk food anymore. I didn't believe that until I did it. Good luck on your journey to weight loss and health! :)
I've been a vegetarian for over 20 years. Vegetarian does not necessarily mean "healthy".
As with any lifestyle, just eat real food. Simple (not always easy, but simple).