I disagree with vegetarianism on a number of points, including its effectiveness as a diet.
if you want to get healthy, I would recommend a semi-vegetarian diet, which is mostly plant-based but includes chicken and fish. of course, you should also cut junk food, fast food, and soda. that way, you'll get the nutrition you need, while avoiding the trans fats and high fructose corn syrup that lead to widespread obesity.