Re. animals proteins.
Our body is not designed for eating animals.
Creator did not give us the right to take the life of our Creator's
sentient beings with a soul; and He did NOT design us for this. Just
because a person states this is in "holy book", doen't mean it is true. I actually assumed this for 10+ years, but eventually I was willing to question my premise.
Some evidence re. how the body of the human is designed:
we are primates, designed best for a plant predominant diet, many
people have a limited capacity to digest animal proteins efficiently.
When we eat a diet rich in animal protein, our ability to efficiently
cleave all the amino acid bonds may be limited. All the protein may not
be totally broken down into its amino acid building blocks. There is
evidence that when animal peptides (pieces of partially broken-down
proteins) are absorbed. They can lead to the formation of antibodies
against themselves. Our immune system will not only attack these foreign
proteins, but it can also cross-react, attacking human proteins in the
body that resemble the amino acid sequences found on dietary animal
other words, because animal proteins closely resemble the amino acid
sequences of human body proteins, our own reaction (antibodies) against
inadequately broken down proteins (peptides) can also attack our own
tissues. Plant proteins are less likely to cause this reaction, even if
their peptides pass into the bloodstream, because they bear little
resemblance to human proteins. Because we cannot efficiently dissolve
animal proteins in the digestive tract and, frequently, consumption
exceeds the digestive capacity, more incompletely digested peptides are
apt to be absorbed. These peptides also results in the stimulation of
unhealthy bacterial flora and the absorption of toxic bacterial
by-products, which can create an inflammatory environment and, hence,
immune dysfunction." [Quote: http://www.drfuhrman.com/disease/arthritis.aspx ]