Lets talk about Meat Eating - is there a true, viable alternative?

Most of the mainstream is raised to think that meat -eating is necessary for living life.  But people are waking up to the question - is it really necessary or is meat merely a choice?  For example, how do horses grow so big and strong, yet they never eat a morsel of meat?  Same thing with cows or baleen whales and many other animals.  If they can live life without a diet of meat, it should be just as possible for humans to do so.

But what is the alternative?  What is the diet which will give you the nutrition and energy which you need? 

We need to talk about this.  We also need to talk about when it seems that meat- carnivorism - is perhaps temporarily necessary.  Vegetarianism is coming out as a way of life which is useful in most cases, for most of the time.