https://www.healthline.com/nutrition/vegan-vs-vegetarian What Is a Vegetarian Diet? According to the Vegetarian Society, a vegetarian is someone who does not eat any meat, poultry, game, fish, shellfish or by-products of animal slaughter. Vegetarian diets contain various levels of fruits, vegetables, grains, pulses, nuts and seeds. The inclusion of dairy and eggs depends on the type of diet you follow. The most common types of vegetarians include: Lacto-ovo vegetarians: Vegetarians who avoid all animal flesh, but do consume dairy and egg products. Lacto vegetarians: Vegetarians who avoid animal flesh and eggs, but do consume dairy products. Ovo vegetarians: Vegetarians who avoid all animal products except eggs. Vegans: Vegetarians who avoid all animal and animal-derived products. Those who do not eat meat or poultry but do consume fish are considered pescatarians, whereas part-time vegetarians are often referred to as flexitarians. Although sometimes considered vegetarians, pescatarians and flexitarians do eat animal flesh. Therefore, they do not technically fall under the definition of vegetarianism. What Is a Vegan Diet? A vegan diet can be viewed as the strictest form of vegetarianism. Veganism is currently defined by the Vegan Society as a way of living that attempts to exclude all forms of animal exploitation and cruelty as much as possible. This includes exploitation for food and any other purpose. Therefore, a vegan diet not only excludes animal flesh, but also dairy, eggs and animal-derived ingredients. These include gelatin, honey, carmine, pepsin, shellac, albumin, whey, casein and some forms of vitamin D3. Vegetarians and vegans often avoid eating animal products for similar reasons. The largest difference is the degree to which they consider animal products acceptable. For instance, both vegans and vegetarians may exclude meat from their diets for health or environmental reasons. However, vegans also choose to avoid all animal by-products because they believe this has the largest impact on their health and the environment. In terms of ethics, vegetarians are opposed to killing animals for food, but consider it acceptable to consume animal by-products such as milk and eggs, as long as the animals are kept in adequate conditions. On the other hand, vegans believe that animals have a right to be free from human use, be it for food, clothing, science or entertainment. Thus, they seek to exclude all animal by-products, regardless of the conditions in which animals are bred or housed. The desire to avoid all forms of animal exploitation is why vegans choose to forgo dairy and eggs — products that many vegetarians have no problem consuming.