Growth problems. Animal population problems. Disease. These are all problems caused by being a vegetarian, that is, one who only eats vegetables. There are different degrees of being a vegetarian. To one extreme, is a person who eats nothing associated with animals (no yogurt, ice-cream, or even anything that has come in contact with meat or another animal). The opposite are those who just eat vegan most of the time and will still eat animal bi-products. Then there are others who are in between.
Being a vegetarian is not natural. Since the beginning of time, humans have been consuming animals. A vegetarians diet lacks energy, calcium, zinc, and vitamins (B-12 and D). Without supplements, severe medical problems can arise. Also, those supplements are usually man made and do not require some of substances, still un-identified, in meat.
A carnivorous diet has always been in American history. Turkey is eaten on Thanksgiving, not Tofu Surprise.
Fish on Fridays, not salad. Pop and son would go hunting in the winter for fresh game to eat, they wouldn't go picking berries and roots. Those who could not or would not eat meat did not survive.
Studies have been done by M. J. Lentze, a German who found that vegetarianism causes impaired growth in children five years or younger. Vegan children even fail to grow as well with supplements that exceed the Recommended Daily Allowance.
It is true that many vegetables contain a high amount of protein, but the amount is not even close in comparison to meat. To get the same amount of protein from vegetables as you would from just one pound of meat (although most people don't eat this much meat anyway!), you would be eating for hours.
Most people become vegetarians because of the Animal Rights Movement...