Why should you go vegan? There are many reasons:

1. The environment. Only a small fraction of the calories consumed by farmed animals are actually converted into the meat that people eat. This means that by raising animals for meat, we are literally wasting about 130 times as much excrement as the entire human population of the United States, and since factory farms don't have sewage treatment systems as our cities and towns do, this concentrated slop ends up polluting our water, destroying our topsoil, and contaminating our air. Raising farm animals is responsible for the production of 86,000 pounds per second! Whether it's the overuse of resources, unchecked water or air pollution, or soil erosion, raising animals for food is wreaking havoc on the Earth.
2. Animal welfare. Farm animals do not have any legal rights. They cannot speak for themselves. They are almost always housed in horrible conditions with almost no room to move. Sanitation is ignored as well. They must sleep in their own feces. And then they are systematically killed by the cheapest methods possible. Often times, the cheapest methods of death are also some of the most painful ways to die. It’s no wonder why there are so many recalls on meat for being diseased.
3. Your health. Vegetarian diets are generally healthier than meat based diets. A vegetarian diet can lower blood pressure and reduces the risk of heart disease (which is the #1 killer in the US).Your calorie intake will probably be reduced,thus you will probably lose some weight (if you eat healthy foods, not vegetarian junk foods). Usually, vegetarians consume more fiber than meat eaters, which profoundly decreases the risk of colon cancer. There are many more heath benefits.
4. You may discover a whole new world of foods. There are so many wonderful ingredients that people completely overlook like seitan, tofu, nutritional yeast, curries, tempeh, exotic spices, lesser known veggies, etc. Similarly, there are so many cultural cuisines that most people don't even try that are full of flavor and have a good selection of vegan choices like Thai, Indian, Moroccan, Vietnamese, Ethiopian, Bengali, and Mediterranean. You may encounter chefs preparing vegetarian feasts concentrating on perfecting the balance of ingredients and spices to optimize the taste of food. When well
prepared, vegetarian meals can be quite astounding.

This has been an excerpt from The Definitive Guide To Vegetarianism

Be sure to check out my vegan recipe eBook: 1000 Vegan Recipes