The basic rule is: No harm to nor even inconveniencing of animals. Not in diet nor lifestyle nor even in the packaging things come in. That means no animal products whatever including leather, wool, feathers, eggs, fish, silk, honey (insects are animals too), milk or anything that has been tested on animals - anything at all.
As you can see this requires a major adjustment of lifestyle and an almost obsessive attention to everything in one's local environment. It is also going to annoy and inconvenience the people around you and severely restrict your social opportunities, so be prepared for that. If you wish to call yourself a vegan you do need to go the whole way. If you don't, real vegans will despise you and you've already pissed off everyone else, so you'll have no friends at all.
Veganism is a modern "ethics" issue and can in no way be considered a "natural" diet. In nature, humans could not survive on a vegan diet - available food choices would be insufficient. Also, without vitamin B12 supplemens, your nervous system would not be working right, making you easy prey, to be promptly killed and eaten by those cute, cuddly animals. Evolution itself depends on critters eating each other, and vegans would be naturally deselected.
If you've thought through these factors and are still committed to being a vegan, then by all means go for it. Be aware that in extreme cases the social isolation can lead to involvement in underground PETA direct action, vandalism, arson and prison. Good luck to you.Health Considerations
Information in this article is based on many publicly available sources. Please refer to our Medical Disclaimer
Vitamin B12: Of all the classes and types of vegetarians who are actually getting enough food, only strict vegans face a serious deficiency problem - lack of vitamin B12 (cobalamin). B12 is produced by soil bacteria, eaten by herbivorous animals along with the plants they eat, and concentrated by them. Humans normally get their B12 from eating animal products (meat & dairy), but this is not allowed for vegans.
Severe B12 deficiency results in nervous system damage and severe anemia. Most at risk of severe deficiency are long term strict vegans who reject supplements, and breast fed infants of vegan mothers. Less severe deficiency can result in heart disease and complications during pregnancy.
The short take is that vegans need to consume adequate B12 supplements. Many vegans resist this, denying there is a problem and pointing out that causes other than veganism are much more common in B12 deficiency. Others point to vegan cultures in India that do not suffer B12 deficiency, but this has been shown the result of food contamination by insects and other animal derived substances.
There have been hopes for a vegetable source of B12. First the great hope was spirulina, then tempeh. In both cases, when these were produced in a sanitary environment, the B12 disappeared. It was from insect, copepod and other animal contamination. Today, B12 supplements for vegans are produced in vats by genetically engineered bacteria, not exactly a "natural" source.
Raw Foods Vegan: This form combines the nutrition problems of both the raw foods diet and veganism, and usually includes a level of idealism that rejects supplements and other "unnatural" resources. See our Raw Foods Diet page for further details.
Failure to Thrive Most people leaving the Standard American Diet for a vegan diet feel their health much improved, but a very significant number who have been vegans for some years eventually encounter a "failure to thrive" problem. This is manifested as general lassitude, being continually hungry, poor sleep, low libido, alienation and mental deterioration among other symptoms. This problem is particularly common among raw food vegans and frutarians. The condition is relieved by re-introducing some animal foods into the diet, but this can have social reprecussions in the vegan community.
Other issues Other nutrition and health considerations are the same as for general vegetarians described on our Vegetarian Diet page.Links