The answer is simple nature did not design humans to eat only plants. A balance of all foods in moderation is the only way to have a heathy body.. Anyone that tells you should ONLY should make you worry right off the bat.. Dont let the opinions of others pressure you into thinking you have to be one or the other... Eating meat is health no matter what the tree hugger say..
Pros: done properly, can be healthy; reduced intake of fats and cholesterol; ethical Cons: lots of people don't know how to create an appropriate vegetarian diet, and become nutrient deficient; difficult to eat out; must properly supplement diet.