A vegetarian is a person who excludes food products derived from the slaughter of animals (generally mammals and birds) from their diet. Depending on the individuals preferences and beliefs, some animal products such as eggs, milk, dairy products and fish may be part of the diet. A person who excludes all animal based products from their diet is generally referred to as a vegan.
For the most part, vegetarian diets are very healthy, and certainly contain less fat and more nutrients than omnivorous diets. There are generally only two problems that can arise with such a diet:
- Vitamin B-12 deficiency - Vitamin B-12 is not found in plants and vegetarians must usually take supplements. Milk contains adequate B-12. Some plants are thought to contain B-12, but this contention is quite controversial.
- Lack of essential amino acids - Humans cannot synthesize certain amino acids and must extract them from the diet. No plant contains all the necessary amino acids, but all the amino acids can be found in plants. For example, rice and beans are both lacking essential amino acids, but together they provide all the necessary ones.
People become vegetarians for a variety of reasons, including religious beliefs, ethical problems with the treatment of animals, and for perceived health benefits.