Veganism
Veganism is the the practice of abstaining from meat
How is it different from vegetarians?
Dietary vegans refrain from comsuming animal product
What are some examples that vegetarians can consume but vegans can't?
They follow a philosophy .The are followers of either the diet is know as a vegan 
Why do you think people choose to become vegan?
Most of them become vegan they want reduce the risk of chronic disease such as heart disease 
But couldn't they just eat healthier in general and continue to consume animal product?
Yes. There are different categories of vegans