I am thinking about starting a vegetarian diet. This means I would not consume the flesh of any animal.
That sounds healthy!  What are the advantages of a vegetarian diet over eating animal protein?
aesthetic, economic, or personal preference. There are variations of the diet as well: an ovo-lacto vegetarian diet includes both eggs and dairy products, an ovo-vegetarian diet includes eggs but not dairy products, and a lacto-vegetarian diet includes dairy products but not eggs. A strict vegetarian diet – referred to as "vegan" – excludes all animal products, including eggs and dairy. Avoidance of animal products may require dietary supplements to prevent deficiencies such as vitamin B12 deficiency, which leads to pernicious anemia.
China study, that appears to link the consumption of animal protein with the development of cancer and heart disease. He argues that casein, a protein found in milk from mammals, is "the most significant carcinogen we consume". 
Campbell has followed a "99% vegan" diet since around 1990. He does not identify himself as a vegetarian or vegan because, he said, "they often infer something other than what I espouse". He told the "New York Times": "The idea is that