Unfortunately, due to the highly restrictive nature of the diet, vegans are at risk of being deficient in certain nutrients such as calcium and vitamin B12 usually found in dairy and meat respectively.

Soybeans used in U.S. tofu and tempeh products aren't grown here. Most of the soybean products (like tofu and tempeh) in the U.S. aren't grown here, the study found. Up until recently, they were largely imported from India, where soybean production contributes to widespread deforestation and habitat loss.

Preventing the exploitation of animals is not the only reason for becoming vegan, but for many it remains the key factor in their decision to go vegan and stay vegan. Having emotional attachments with animals may form part of that reason, while many believe that all sentient creatures have a right to life and freedom.