Some will argue that because we have canine teeth this is evidence that we have been 'designed' to eat meat, ie it is 'natural'. However, even if our ancestors had to eat meat to survive, we certainly don't need to today. Supermarkets enable us to choose from thousands of vegetarian products. The human digestive system is perfectly in tune with a vegetarian diet, therefore, if we want to choose to be vegetarians, we can. Isn't vegetarianism is unhealthy Chocolate and chips are vegetarian, however, they do not represent a balanced diet.
Vegetarianism is a healthy choice as long as a wide range of foods is eaten.
This also applies to a meat diet. Research has compared a healthy meat diet to a healthy veggie diet. It was found that the vegetarian diet was the healthiest. Some vegetarians would eat meat in this situation, others wouldn't. However, the chances that we would find ourselves in this situation are so slim, it would be up to the individual to decide what to do.