Vegetarians frequently choose their diet for religious or political reasons, as well as for the reported health benefits. Vegans have much stronger ethical and environmental beliefs about their diet in general, with some believing that animals should be protected like humans.

Some people eating a plant-based diet may choose not to eat meat and animal products for various reasons. A vegan diet excludes all meat and animal products (meat, poultry, fish, seafood, dairy and eggs), whereas a vegetarian diet excludes meat, poultry, fish and seafood.

Vegetarians don't eat any food products made from meat, fish, shellfish, crustacea (such as prawns or crab) or animal by-products (such as gelatine or rennet). Vegans don't eat any food products that come from animals, including dairy products and eggs.

A vegan diet is another form of vegetarianism where only plant foods are eaten and all foods from animal sources are avoided (meat, seafood, dairy, eggs and sometimes honey and gelatine).