There's nothing wrong with the vegetarian diet, when done correctly. There's also nothing wrong with a "meat eating" diet, when done correctly. The problems occur when these diets are done incorrectly. You know, the vegetarian who eats cheese pizzas and ramen noodles 24/7 or the meat-eater who camps out at Burger King all day.
Vegetarians still have plenty of great sources of fats and proteins - eggs and milk. Even vegans still have good sources of fats and proteins - beans, mainly soybeans, rice protein, etc.
I still think that meat-eating is superior, since man is a meat-eating animal. We were built to run off of proteins and fats found in animals (e.g. the omega 3's found only in animal sources). But even so, that doesn't mean that all vegetarians and vegans are automatically unhealthy.
I think all of these stories about ghastly and skinny vegetarians/vegans are overstated. A vegetarian/vegan could easily point to an overweight meat-eater. The key is to know your nutritional requirements and to follow them judiciously. That might be a little more difficult for the vegan, but it's still doable.
All of that said, it kind of annoys me when people become vegetarian or vegan for "health reasons." Whenever anyone says that they're a vegetarian because meat-eating is unhealthy, I write them off as an uneducated ******* who's afraid of dietary fat.