There has been an increasing interest in vegan diet in recent years. To understand what a vegan diet is, it is important to understand what veganism is first.
According to Vegan Australia website, Veganism is a social justice movement that is striving to bring about a world where animals are not exploited for food, clothing, entertainment or any other purpose(1). Therefore, a vegan diet is one that is totally plant-based and exclude all animal foods as well as animal-derived ingredients. Obvious foods such as meat, chicken, fish to egg, milk are excluded. Other not so obvious ingredients such as gelatine in marshmallow or jellies, some natural food colouring (e.g. red in cochineal which is an insect) and glycerine are excluded in a vegan diet.
From a nutrition point of view, with careful planning a vegan diet is able to provide all nutrients from everyday foods, with the exception of Vitamin B12. When I say careful, I means really careful - making sure you have enough protein, calcium and iron from your meal. Simply omitting all animal based products and increasing fruit and vegetable intake is not a vegan diet.
One exception is Vitamin B2. Vitamin B12 is only found naturally in animal products, being originally derived from bacteria. Main symptoms of Vitamin B12 deficiency includes anemia, neurological symptoms and gastrointestinal symptoms. Therefore, a vegan diet is only complete with supplementation of Vitamin B12 or consuming adequate amount of fortified foods.
Replacing animal based foods with plant based diet have many benefits - from a health and animal right perspective, to environmental and sustainability perspective. Talk with someone who is already following a vegan diet for a long time and to explore and ask questions first. Consult a dietitian if it helps you plan your meals better.