My two cents.. In Chinese medicine, foods have different energetic properties, and are used to balance the particular imbalances that you have. In other words, there is no one-size-fits-all diet, but you aim for balance, and what that requires will be different for different people.
For example, I had been a strict vegetarian for many years, but because of my cold and deficient constitution and living in a cold climate, a small amount of animal protein was necessary for me to rebuild my health. By contrast, someone who has eaten a lot of meat for a long time and who has a warmer constitution, may do better on a vegetarian diet, but as the Tao is ever-changing, we have to adjust to ever-changing circumstances and be able to be flexible and make changes as they become necessary.
Most people who are involved in a meditative lifestyle will want to eat in a way that incurs the least harm, but there are many ways to do that. Basically, it is a very personal issue, and no one (including me!) should tell you what to do about diet, and you shouldn't follow any approach just because it's politically correct, but to really penetrate the matter within yourself and find out what is right for you. I found that understanding what my body really needed from a Chinese medicine viewpoint, despite what I thought I was supposed to eat in order to be spiritual, was a tremendous help.
Having soul-searched this many years, I've come to different conclusions at different times of my life, but that's the process 
