There have been some interesting findings in neuroscience about how food can generate reactions in the brain. Former FDA Commissioner, David Kessler wrote a fascinating book about how fat, salt and sugar light up specific areas of the brain that are responsible for addiction.
For many who are intolerant of gluten and casein, these act like an opiate on the brain and even though ingesting them cause great discomfort they nonetheless generate a profound craving.
My point being that perhaps some kind of neurological response is involved. Perhaps you can use I/M to get to your answer. Good luck.