Why should people consider becoming vegan?

To add to the answer given previously, veganism is seen as a scary concept for some. It's hard to imaging totally changing one's diet. However, it is completely plausible. These days, the fitness community is pandering more towards people who might be interested in the vegan lifestyle. These include preparing vegan-style diets or vegan-style supplements.
The fact of the matter is, it's becoming more and more of an accepted practice. No longer would one have to feel marginalized based on the constraints of society.
For example, there's a big emphasis on macronutrients when it comes to dieting and building up your body. This takes form in the way of literally breaking down everything that goes into your body. All the fat, all the protein, and all the carbohydrates. In this case, there's always been a focus that leans more towards foods that are low in fats but high in carbohydrates -- which is what provides energy.
It's a logical alternative. That's what veganism is now. It's logical and completely accepted. It's no surprise then, that more people are considering the changeover from one diety to another.

There are several reasons why someone might consider becoming vegan. Some believe that it is a more sustainable way of living because the plant based diet requires less space to maintain than raising animals for food and therefore, better for our environment.
Another reason are the health benefits of a plant based diet. A vegan diet consists of fruits and vegetables, grains, and beans and legumes. Additionally, a vegan diet avoids any foods that come from animals such as milk, meat, and eggs as well as foods processed with animal byproducts such as gelatin. Research has linked a vegan diet with lower cholesterol and blood pressure and the prevention of certain diseases including Type 2 diabetes and some cancers. A vegan diet could also contribute to a healthy weight as this type of diet generally is much lower in unhealthy fats.
In addition to the the health benefits, many people choose to live a vegan lifestyle to prevent cruelty to animals. This includes not only eating a vegan diet, but also avoiding cosmetics and other products tested on animals and clothing made from animals such as leather, wool or other furs.

There are several reasons many people might wish to reduce their reliance on animal products or become totally vegan.
The first reason is ethical. Many people believe that killing other living beings when there is no need to do so is ethically wrong. Also, as many vegans point out, factory farming is inhumane, with the animals living in constant pain and distress until they are slaughtered.
Next, there are strong environmental reasons for going vegan. It takes several times more grain and water to feed animals to produce a pound of meat than it does just to produce grains for human consumption. Also, cattle, especially. produce methane, which is a greenhouse gas.
Additionally, going vegan saves money. It is far less expensive to buy a pound of legumes (which are high in protein and vitamins) than a pound of meat.
Finally, a vegan diet has several health benefits, including improved cardiovascular health, weight loss, and reduction in the probability of getting certain types of cancers.