There are a lot of reasons a person would choose to follow a vegan diet. The most common reasons are for health and animal rights.
Health: Most people choose to follow this diet because of health purposes. The vegan diet is more healthier than a carnivorous or omnivorous diet, as it only permits the eating of fruits and vegetables.
Animal rights: Most people choose to follow the vegan diet because they are animal advocates, meaning they are against the killing of animals for food and clothes.