I have tried to cut out as much red meat as possible recently. I was taken in by some of the accounts of vegetarian friends and others who described the energy they had and attributed to the fact that digestion of complex protein chains requires lots of energy and can leave you lethargic naturally.
I do believe that most people eat way too much meat in general and that in our natural state, if there is even such a thing, our diet would consist mainly of the things we could grow and forage easily and be supplemented by the food that we needed to hunt or defend from predators in the case of livestock. I think this fits in well with a path of least resistance philosophy which I think is as natural as a plant growing toward light or villages sprouting up by fresh water sources, etc.
Before conducting my experiment, I did a fair bit of research on the foods that were available to supplement the protein I would be missing. I didn't want to end up extremely deficient in a vitamin or mineral and end up exposing myself to disease or weakness.
It was during this research that I had determined that there is no possible way that humans were meant to be vegan, and mainly for three reasons, B12, Zinc, and Coenzyme Q10.
These essential ingredients are almost exclusive to animal flesh and are absolutely necessary to a normal functioning human body.
Without finding foods that were "fortified" with B12, the only other place to find it in any quantity is in algae and medical research has indicated that it does not work as a viable replacement:
Vitamin B-12 from algae appears not to be bioavailable.$1:
The effect of algae (nori and spirulina) and fermented plant foods on the hematological status of vitamin B-12-deficient children was evaluated. Although rising plasma vitamin B-12 concentrations in children consuming only plant foods (0.1-2.7 micrograms vitamin B-12/d) indicated that the vitamin B-12 was absorbed, elevated baseline values of mean corpuscular volume (MCV) further deteriorated. In contrast, MCV improved in children receiving fish containing 0.15-0.5 microgram vitamin B-12/d or a vitamin B-12 supplement. Further studies on the specificity of current vitamin B-12 assays are warranted. It seems unjustified to advocate algae and other plant foods as a safe source of vitamin B-12 because its bioavailability is questionable.
http://www.ncbi.nlm.nih.gov/pubmed/2000824Again zinc can be found in beans, lentils, peas, seeds, but because the levels are so low, you would end up over consuming in order to achieve the required levels that you could easily obtain from a small amount of meat. A high percentage of vegitarians are zinc deficient for this reason.
Lastly, Coenzyme Q10 is necessary for the proper function of every cell in our body and although it can be found in spinach broccoli cauliflower and other members of the cabbage family, you need to consume a lot of it to maintain safe levels.
Interestingly, these missing ingredients are generally highest in fish, and being from the east coast, I love my fish so that has been my main non vegetarian supplement but I do still enjoy a steak or pork chop once in a while because I think it is healthy to do so.
I'll admit that the changes in my diet have given me more energy, I still enjoy my meat though and believe it is completely natural for us to eat it, just not as much as some do.