When Nancy Attia, 41, a restaurant owner, first saw the Egyptian doctor Diaa al-Awady in a video, she was "appalled by his aggressive attitude." The man, who would go on to garner nearly 3 million followers on his Facebook page and become a viral sensation in the Arab world months after his death, was espousing a diet called “tayyibat” that would soon become something akin to an anti-scientific cult with adherents across the Middle East. Five mo…