I have been reading a lot about vegetarianism. Are you on any special diet. 
I just try to watch what I eat. I have heard vegetarianism has its roots in India and Greece
I am a environmental vegetarian I guess. Industrial animal places are bad for the environment and meat isn't good for humans , or so I've read.
I understand why people practice veganism. Most people do no want to harm animals and prefer a plant based diet.
Supposedly the human digestion system or colon is much longer than an animals because we are supposed to have a plant based diet as opposed to the short colons animals that eat meat have.
I remember reading about some monks who did not eat any meet or use any animals products. But they did choose to eat fish so I guess they were not full vegan.
Yes there seems to be a lot of different varieties of it.  Some don't eat packaged or processed foods that have animal ingredients.
banned the consumption of meat for ascetic reasons, but none of them abstained from the consumption of fish; these monks were not vegetarians, but some were pescetarians. Vegetarianism was to reemerge somewhat in Europe during the Renaissance and became a more widespread practice during the 19th and 20th centuries. The figures for the percentage of the Western world which is vegetarian varies between 0.5% and 4% per Mintel data in September 2006. 
Ancient.
Ancient Indian subcontinent.
Ancient Indian subcontinent Early Jainism and Buddhism.
Jain and Buddhist sources show
Jewish vegetarianism
Jewish vegetarianism is a commitment to vegetarianism that is connected to Judaism, Jewish ethics or Jewish identity. Jewish vegetarians often cite Jewish principles regarding animal welfare, environmental ethics, moral character, and health as reasons for adopting a vegetarian or vegan diet.
Ancient and Medieval.
Genesis 1:29 states "And God said: Behold, I have given you every herb yielding seed which is upon the face of all the earth, and every tree that has seed-yielding fruit—to you it shall be for