It's not that important to be an omnivore, but if you're a vegetarian/vegan, it's harder to get certain essential nutrients. They both have to worry about iron and protein, and vegans have to worry about calcium and vitamin D, but you don't really have to worry if you take a multivitamin. As long as you eat a varied diet (with whole grains, beans, etc.), you should be fine.

There really isn't any grater risk of missing out on nutrients being a vegetarian or vegan than someone who eats a high protien/heavy meat diet. Everyone should eat a balanced diet, no matter where they are getting their nutrients from (meat, soy, dairy...). As a group, vegetarians/vegans tend to be a bit healthier than meat eaters.

Drawbacks? Ha. All the biggest, strongest creatures on earth are vegetarian (elephants, rhino's, gorilla's). The worlds top athlete, Dave Scott, the only man to ever win the Ironman Triathlon more than once (4 times) is a vegetarian as are most the top atheletes of the world. A study was done by Dr. J. Ioteyko of the Academie de Medicine of Paris. Dr. Ioteyko compared the endurance of vegetarians and meat-eaters from all walks of life in a variety of test -"vegetarians averaged two to three times more stamina than the meat-eaters. Even more remarkably, they took only one-fifth the time to recover from exhaustion compared to their meat-eating rivals." From personal experience growing up vege - I won the presidents physical fitness award in 2 different high schools -y'know "the Presidents List" -I got 2 letters from the President...I was faster than the fastest boy on the football team (I'm female)...I could run circles around them all without barely trying... Now I'm in my 30's but everyone thinks I'm in my early 20's...people think that my kids are my little brothers... There are no drawbacks to not eating animal corpses. Unless you only eat cheetos or something. But if you're eating lots of veggies you'll be more than fine. Eat lots of colors...especially green. The oldest peron in recorded history who lived to 122 was vegetarian.