Aslan, an Iranian-born religious scholar, was with a group from the Aghori sect when he was invited to eat cooked brain tissue during a ritual.
Aslan, 44, met the Aghori in the holy Hindu city of Varanasi in Uttar Pradesh, where they smeared the ashes from cremated human bodies on his face.
He then drank an alcoholic drink from a human skull, before eating what he was told was human brain.
At one point he fell out with the Aghori guru who shouted: "I will cut your head off if you keep talking so much."
The guru began eating his own faeces and then hurled it at Aslan.
Aslan quipped: "I feel like this may have been a mistake."
Indian-Americans have criticised CNN for highlights the beliefs of a tiny cult - which has less than 100 members - which has little to do with mainstream Hinduism.
The Aghori are devotees of the Hindu god Shiva and believe nothing can taint the human body. But their beliefs and practices are rejected by orthodox Hindus.
The Hindustan Times reported that the US India Political Action Committee said in a statement: 'With multiple reports of hate-fueled attacks against people of Indian origin from across the US, the show characterises Hinduism as cannibalistic, which is a bizarre way of looking at the third largest religion in the world."
Industrialist Shalabh Kumar told the Press Trust of India: "This is a disgusting attack on Hinduism."
Kumar tweeted: "CNN, Clinton News Network has no respect for Hindus. All Hindus worldwide should boycott CNN."
He also claimed the Republican Hindu Coalition was "planning to take major action".
Then, in an extraordinary outburst, Kumar tweeted: "I condemn CNN for airing Believer with fiction. Disgusting attack on Hindus for supporting @POTUS @stephenkbannon @newtgingrich."
Kumar had previously claimed that 65 percent of Hindus in America had voted for Trump.