Vegetarians and Theists

Does it ever appear to be a contradiction when you meet a vegetarian who is an evolutionary atheist (EA). It always seems odd to me for the following reasons. If one is to look at the theory of evolution, there are basically four areas that a species would want to increase their fitness in, in order for their species to gain better traits and lose bad ones. The four areas are feeding, fighting, flighting, and reproducing (these basics are borrowed from Plantinga’s evolutionary argument). So, it seems that to excel in the areas of flighting and fighting, one would want the optimum diet, as well as, the optimum training regimen to make a specific species stronger.

This is where the problem enters.

A strictly vegetarian diet is not the optimum diet, in fact, we all know that the optimum diet would include various kinds of meat (specifically Chicken, fish, and other seafood). So, when an EA decides to be a vegetarian, they are actually not wanting their species to be the fittest (especially if you are a rational being…like a human), and therefore the species will eventually die off. The problem is that they are still around, and so I want to know what the justification for that is. My conclusion, is that all vegetarians ought to be theists, or else they shouldn’t be vegetarians because they are dragging down our species.