First off, the main idea of veganism and vegetarianism is not to lose weight. If you are going to become either one you better have the right idea in mind, more about caring for animals and the treatment of them.

Losing weight-wise, it all depends on what the vegan eats on a daily basis and how much calorie intake they get. I am a vegetarian and its not like im a stick or anything. Just because you dont eat meat or chicken or anything like that doesnt mean you are going to lose the weight faster. Some meats are actually healtier than just skipping out on them completely. The key to losing weight is the balance of diet, exercise, and healthy choices. Not being a vegetarian or vegan.