Wow a lot of people just rationally thought, "Well this seems like the sensible option..."
Then we have the, "I felt shitty then tried eating like a human and now I like it."
For me it was straight rage. I am often filled with hatred for agents of cancerous oppression, against whom I have no means of retalliation, and so instead I just started internalizing it and liking the feeling of destroying muscle tissue, and of regeneration and overcoming. I remember though a few years ago just before I started actually taking control of my nutrition that first for a few weeks I just punched a knotted drape that hung in the kitcken doorway.
"Ah, those endless forests, and their horror-haunted gloom! For what eternities have I wandered through them, a timid, hunted creature, starting at the least sound, frightened of my own shadow, keyed-up, ever alert and vigilant, ready on the instant to dash away in mad flight for my life. For I was the prey of all manner of fierce life that dwelt in the forest, and it was in ecstasies of fear that I fled before the hunting monsters."
Jack london, "Before Adam"