It is obvious from humans not having the large abdomen and long gut of great apes, who are essentially fructivore/herbivores, that humans are adapted to omnivory. Apes are 'hind gut fermenters' they have large colons where commensal microbes help to break down cellulose and other plant polysaccharides. The colon is 17-23% of total gut volume in humans, while it is 52-54% in orangutans and chimpanzees. The take home message from comparative anatomy is that omnivory, including some fish and meat, is a more suitable diet for humans, than strict herbivory.
It is completely different. Ethical and religious reasons are not the same and, despite all religions teaching compassion, very few religious people truly show it. So, their religious practice is rarely ethical.
It has some similarities. Foods that are acceptable and those that are not, parallels Judaism, Islam and Hinduism. It also has a fanatical wing that is not above breaking the law.
