I started eating only vegan food last summer - I was doing some detoxing and was on a raw food diet which is vegan. Then I went to Rainbow Gathering in Wyoming and read some pamphlets on how farms treat the animals cruelly. Even the organic and free range chickens may not be so free on a large farm. When we were driving out of the Rocky mountains on the way home, we stopped at an all night dinner and I ordered steak and eggs. The food was good quality but my stomach hurt as I ate it and I didn't sleep well all night long. I think it was a message from my body to not eat this kind of food. So I chose to become vegan that morning. It was both a health issue, a spiritual issue and a green issue for me. (Green because to produce the same amount of nutrition from meat takes 2-10 times as much resources as from plant food).
Since then I have either eaten vegan or raw food. I did slip once last year when I had a craving for chicken but adding more protein (nuts, hemp milk, beans) to my diet solved that problem. I feel healthy and I have lost about 10 lbs too.
Here is a link to the cover article in Time Magazine that makes a strong arguement for re-evaluating our food choices (and it's packaging)
http://www.time. com/time/ health/article/ 0,8599,1917458, 00.html