So why are foods that you're allergic to/sensitive to so darned addictive?
The process is complex, but many researchers feel it's coming clear. A food allergy reaction begins in the stomach with enzymes. We each have certain enzymes to digest particular proteins (and by particular, I mean VERY particular--a person can be allergic to East Coast shrimp but not West Coast shrimp); we can also, in effect, "use up" our supply of enzymes for a particular protein by overconsumption of that protein.
Wheat, dairy, and chocolate all have proteins. Yes, the amounts in chocolate and wheat seem small from the protein-counting dietary perspective, but from the enzymatic perspective, it's plenty to trigger the full-blown allergic reaction. The digestion of these "bad" proteins causes the release of a series of peptides which provide feedback to the brain. Some normal peptides that tell us we're full may not be released at all.
But some other peptides are released that are very similar to heroin in their effect: exorphins. As the brain receptors take in the molecules, we get high briefly. (at the same time, realize, if the food was high carb too, we also get a brief blood sugar high, then a precipitous drop). However, after the exorphin high comes a low...and if we feed that low with another dose of bread, chocolate, or LC cheesecake, the high that results is much less (the receptor reuptake mechanism hasn't done its thing yet--it's the same reason that you can't get high taking LSD several days in a row). I suspect most of us have had this experience--we start eating more and more of our "beloved" food, trying to get high again, but the food becomes less and less satisfying; often we quit only when physically ill from overeating, still unhappy and unsatisfied.
Other peptides may be released that make you high while still others are released that block the action of normal brain chemicals, perhaps making the user miserable at one level and high at another. One doctor says, "It has been suggested that gluten hydrolysates, digests of wheat protein, have mixed opiate agonist-antagonist activity and, like two drugs with mixed narcotic activating and blocking actions (nalorphine and cyclazocine), produce dysphoria and even psychotic symptoms"
This last is quite interesting--research is being done into this mechanism to explain autism and schizophrenia, among other serious "mental" illnesses. Schizophrenia rates apparently increase in any population
as the dietary intake of potatoes increases--fascinating, eh?
Leaky gut syndrome (which we all get to some degree with grains) may also contribute to the process. There's a lot of research that needs to be done and little that has been done. Some of this is coming out of Japan (perhaps market forces from the food industry don't block this reseach as much there). The good news is that drug comanies have reason to do the reseach because specific replacement enzyme therapy might be profitable.
Yes, there's a genetic component to this, too. You inherit your digestive enzymes. You inherit a risk of food allergy (though the parent and child can have two totally different food allergens). You can inherit the likelihood of food allergy that comes from over-exposure through generations of overexposure. Thus, european/middle eastern ancestory makes you more likely to be allergic to wheat, barley, all gluten. Asian folks tend to develop over-exposure allergies to rice. Allergies to lactose are more common when ancestors didn't get milk (First people/Native americans and Black folk have this allergy) but allergies to casein, a protein in dairy, are more common among Northern Europeans. (that's apparently the "damned if you do, damned if you don't" rule of dairy allergies and ancestory!)
So what to do? 1) Identify then avoid your dangerous foods. 2) try taking an inexpensive digestive enzyme tablet (like Beano) with your LC tortilla or carbolite bar or LC cheesecake--it may help replace the enzymes you're missing. 3) just understand that this is a real, physiological process. this can help some people not go back for "seconds" after a cheat; if we know our brain chemistries will re-settle in a day or two, perhaps we can hang on that long.
See also
http://www.nutramed.com/eatingdisor...ictivefoods.htm ,
http://www.2.waisays.com/zombie.htm, and
http://home.iprimus.com.au/rboon/FOODALLERGIES.htm for some more detail. Definite thanks has to go to two of my students (who shall remain nameless) whose research projects on food allergies and schizophrenia clued me into the current research and led me to my own reading.