https://youtu.be/GO_HgxPsvF0
It leads to malnutrition and mental impairment.
References
Ethical veganism could be considered ‘protected belief’ akin to religion in landmark case
https://www.telegraph.co.uk/news/2018/12/03/ethical-veganism-could-considered-religion-landmark-tribunal/
Veganism is starting to contribute to malnutrition in wealthy countries https://www.businessinsider.com.au/how-vegan-diets-are-affecting-global-health-2018-12